Question: Who is the spouse of the person who defeated the last song emperor of the country that is the biggest owner of US debt?

full_context: Document 1: National debt of the United States: On November 7, 2016, debt held by the public was $14.3 trillion or about 76% of the previous 12 months of GDP. Intragovernmental holdings stood at $5.4 trillion, giving a combined total gross national debt of $19.8 trillion or about 106% of the previous 12 months of GDP. As of December 2017, $6.3 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest of which were Japan (about $1.06 trillion) and China (about $1.18 trillion).
Document 2: National debt of the United States: As of April 30, 2018, debt held by the public was $15.3 trillion and intragovernmental holdings were $5.7 trillion, for a total or ``National Debt ''of $21 trillion. Debt held by the public was approximately 77% of GDP in 2017, ranked 43rd highest out of 207 countries. The Congressional Budget Office forecast in April 2018 that the ratio will rise to nearly 100% by 2028, perhaps higher if current policies are extended beyond their scheduled expiration date. As of December 2017, $6.3 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest being China (about $1.18 trillion) then Japan (about $1.06 trillion).
Document 3: National debt of the United States: As of July 31, 2018, debt held by the public was $15.6 trillion and intragovernmental holdings were $5.7 trillion, for a total or ``National Debt ''of $21.4 trillion. Debt held by the public was approximately 77% of GDP in 2017, ranked 43rd highest out of 207 countries. The Congressional Budget Office forecast in April 2018 that the ratio will rise to nearly 100% by 2028, perhaps higher if current policies are extended beyond their scheduled expiration date. As of December 2017, $6.3 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest being China (about $1.18 trillion) then Japan (about $1.06 trillion).
Document 4: Song dynasty: The Song dynasty (Chinese: 宋朝; pinyin: Sòng cháo; 960 -- 1279) was an era of Chinese history that began in 960 and continued until 1279. It was founded by Emperor Taizu of Song following his usurpation of the throne of Later Zhou, ending the Five Dynasties and Ten Kingdoms period. The Song often came into conflict with the contemporary Liao and Western Xia dynasties in the north and was conquered by the Mongol - led Yuan dynasty. The Song government was the first in world history to issue banknotes or true paper money nationally and the first Chinese government to establish a permanent standing navy. This dynasty also saw the first known use of gunpowder, as well as the first discernment of true north using a compass.
Document 5: Sino-Tibetan relations during the Ming dynasty: Nevertheless, the ethno-geographic caste hierarchy favoring the Mongols and other ethnicities were accorded higher status than the Han Chinese majority. Although Han Chinese who were recruited as advisers were often actually more influential than high officials, their status was not as well defined. Kublai also abolished the imperial examinations of China's civil service legacy, which was not reinstated until Ayurbarwada Buyantu Khan's reign (1311–1320). Rossabi writes that Kublai recognized that in order to rule China, "he had to employ Chinese advisors and officials, yet he could not rely totally on Chinese advisers because he had to maintain a delicate balancing act between ruling the sedentary civilization of China and preserving the cultural identity and values of the Mongols." And "in governing China, he was concerned with the interests of his Chinese subjects, but also with exploiting the resources of the empire for his own aggrandizement. His motivations and objectives alternated from one to the other throughout his reign," according to Rossabi. Van Praag writes in The Status of Tibet that the Tibetans and Mongols, on the other hand, upheld a dual system of rule and an interdependent relationship that legitimated the succession of Mongol khans as universal Buddhist rulers, or chakravartin. Van Praag writes that "Tibet remained a unique part of the Empire and was never fully integrated into it," citing examples such as a licensed border market that existed between China and Tibet during the Yuan.
Document 6: Yuan dynasty: There were many religions practiced during the Yuan dynasty, such as Buddhism, Islam, and Christianity. The establishment of the Yuan dynasty had dramatically increased the number of Muslims in China. However, unlike the western khanates, the Yuan dynasty never converted to Islam. Instead, Kublai Khan, the founder of the Yuan dynasty, favored Buddhism, especially the Tibetan variants. As a result, Tibetan Buddhism was established as the de facto state religion. The top-level department and government agency known as the Bureau of Buddhist and Tibetan Affairs (Xuanzheng Yuan) was set up in Khanbaliq (modern Beijing) to supervise Buddhist monks throughout the empire. Since Kublai Khan only esteemed the Sakya sect of Tibetan Buddhism, other religions became less important. He and his successors kept a Sakya Imperial Preceptor (Dishi) at court. Before the end of the Yuan dynasty, 14 leaders of the Sakya sect had held the post of Imperial Preceptor, thereby enjoying special power. Furthermore, Mongol patronage of Buddhism resulted in a number of monuments of Buddhist art. Mongolian Buddhist translations, almost all from Tibetan originals, began on a large scale after 1300. Many Mongols of the upper class such as the Jalayir and the Oronar nobles as well as the emperors also patronized Confucian scholars and institutions. A considerable number of Confucian and Chinese historical works were translated into the Mongolian language.
Document 7: Song dynasty: The Song dynasty is divided into two distinct periods, Northern and Southern. During the Northern Song (Chinese: 北宋; 960 -- 1127), the Song capital was in the northern city of Bianjing (now Kaifeng) and the dynasty controlled most of what is now Eastern China. The Southern Song (Chinese: 南宋; 1127 -- 1279) refers to the period after the Song lost control of its northern half to the Jurchen Jin dynasty in the Jin -- Song Wars. During this time, the Song court retreated south of the Yangtze and established its capital at Lin'an (now Hangzhou). Although the Song dynasty had lost control of the traditional ``birthplace of Chinese civilization ''along the Yellow River, the Song economy was still strong, as the Southern Song Empire contained a large population and productive agricultural land. The Southern Song dynasty considerably bolstered its naval strength to defend its waters and land borders and to conduct maritime missions abroad. To repel the Jin, and later the Mongols, the Song developed revolutionary new military technology augmented by the use of gunpowder. In 1234, the Jin dynasty was conquered by the Mongols, who took control of northern China, maintaining uneasy relations with the Southern Song. Möngke Khan, the fourth Great Khan of the Mongol Empire, died in 1259 while besieging the city of Chongqing. His younger brother Kublai Khan was proclaimed the new Great Khan, though his claim was only partially recognized by the Mongols in the west. In 1271, Kublai Khan was proclaimed the Emperor of China. After two decades of sporadic warfare, Kublai Khan's armies conquered the Song dynasty in 1279. The Mongol invasion led to a reunification under the Yuan dynasty (1271 -- 1368).
Document 8: Jingnan: The Song Dynasty was formed in 960, ending the Five Dynasties period in the north, and though that is the date traditionally used to denote the end of the Five Dynasties and Ten Kingdoms period, many kingdoms in the south maintained their independence for nearly two decades after the rise of the Song Dynasty. However, due to its size and location, Jingnan was the first of the kingdoms to succumb to the Song Dynasty, surrendering when armies from the north invaded in 963, ending the kingdom.
Document 9: Yuan dynasty: The first recorded travels by Europeans to China and back date from this time. The most famous traveler of the period was the Venetian Marco Polo, whose account of his trip to "Cambaluc," the capital of the Great Khan, and of life there astounded the people of Europe. The account of his travels, Il milione (or, The Million, known in English as the Travels of Marco Polo), appeared about the year 1299. Some argue over the accuracy of Marco Polo's accounts due to the lack of mentioning the Great Wall of China, tea houses, which would have been a prominent sight since Europeans had yet to adopt a tea culture, as well the practice of foot binding by the women in capital of the Great Khan. Some suggest that Marco Polo acquired much of his knowledge through contact with Persian traders since many of the places he named were in Persian.
Document 10: Sino-Tibetan relations during the Ming dynasty: Starting in 1236, the Mongol prince Kublai, who later ruled as Khagan from 1260–1294, was granted a large appanage in North China by his superior, Ögedei Khan. Karma Pakshi, 2nd Karmapa Lama (1203–1283)—the head lama of the Karma Kagyu lineage of Tibetan Buddhism—rejected Kublai's invitation, so instead Kublai invited Drogön Chögyal Phagpa (1235–1280), successor and nephew of Sakya Pandita, who came to his court in 1253. Kublai instituted a unique relationship with the Phagpa lama, which recognized Kublai as a superior sovereign in political affairs and the Phagpa lama as the senior instructor to Kublai in religious affairs. Kublai also made Drogön Chögyal Phagpa the director of the government agency known as the Bureau of Buddhist and Tibetan Affairs and the ruling priest-king of Tibet, which comprised thirteen different states ruled by myriarchies.
Document 11: Yuan dynasty: After strengthening his government in northern China, Kublai pursued an expansionist policy in line with the tradition of Mongol and Chinese imperialism. He renewed a massive drive against the Song dynasty to the south. Kublai besieged Xiangyang between 1268 and 1273, the last obstacle in his way to capture the rich Yangzi River basin. An unsuccessful naval expedition was undertaken against Japan in 1274. Kublai captured the Song capital of Hangzhou in 1276, the wealthiest city of China. Song loyalists escaped from the capital and enthroned a young child as Emperor Bing of Song. The Mongols defeated the loyalists at the battle of Yamen in 1279. The last Song emperor drowned, bringing an end to the Song dynasty. The conquest of the Song reunited northern and southern China for the first time in three hundred years.
Document 12: National debt of the United States: On November 7, 2016, debt held by the public was $14.3 trillion or about 76% of the previous 12 months of GDP. Intragovernmental holdings stood at $5.4 trillion, giving a combined total gross national debt of $19.8 trillion or about 106% of the previous 12 months of GDP; $6.2 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest of which were Japan and China at about $1.09 trillion for Japan and $1.06 trillion for China as of December 2016.
Document 13: National debt of the United States: As of July 31, 2018, debt held by the public was $15.6 trillion and intragovernmental holdings were $5.7 trillion, for a total or ``National Debt ''of $21.3 trillion. Debt held by the public was approximately 77% of GDP in 2017, ranked 43rd highest out of 207 countries. The Congressional Budget Office forecast in April 2018 that the ratio will rise to nearly 100% by 2028, perhaps higher if current policies are extended beyond their scheduled expiration date. As of December 2017, $6.3 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest being China (about $1.18 trillion) then Japan (about $1.06 trillion).
Document 14: Great Divergence: During the Song Dynasty (960 -- 1279), the country experienced a revolution in agriculture, water transport, finance, urbanization, science and technology, which made the Chinese economy the most advanced in the world from about 1100. Mastery of wet - field rice cultivation opened up the hitherto underdeveloped south of the country, while later northern China was devastated by Jur'chen and Mongol invasions, floods and epidemics. The result was a dramatic shift in the center of population and industry from the home of Chinese civilization around the Yellow River to the south of the country, a trend only partially reversed by the re-population of the north from the 15th century. By 1300, China had fallen behind Italy in living standards.
Document 15: Chabi: According to "The Secret History of the Mongols", Chabi was the favorite wife of Kublai and a valued unofficial adviser throughout his reign. She was a patron of the arts and may have played a key role in advancing the interests of the young Venetian traveler, Marco Polo. It is suspected that Chabi herself may have come under Christian influence, like her mother-in-law, Sorghaghtani.
ground_truth: Chabi
sub_queries: who is the biggest owner of us debt Answer: China
who defeated the last song emperor of China Answer: Kublai Khan
Kublai Khan >> spouse Answer: Chabi