Question: Which borders Vietnam, Hekou Yao Autonomous County or Lhasa City?

full_context: Document 1: Du'an Yao Autonomous County: Du'an Yao Autonomous County (zhuang: Duhnganh Yauzcuz Swci Yen ,) is an autonomous county under the administration of Hechi City, in the northwest of Guangxi, China. It has an area of 4095 km2 and a population of 625,100, including 596,100 that are of minority ethnic groups.
Document 2: Lào Cai: Lào Cai (  ) is a city in the Northwest region of Vietnam. It is the capital of Lào Cai Province. The city borders the city of Hekou Yao Autonomous County, in the Yunnan province of southwest China. It lies at the junction of the Red River (Sông Hồng) and the Nanxi River (Yunnan) approximately 160 miles (260 km) northwest of Hanoi.
Document 3: Lhasa (prefecture-level city): Lhasa City is a prefecture-level city, formerly a prefecture until 7 January 1960, one of the main administrative divisions of the Tibet Autonomous Region of China. It covers an area of 29274 km2 of rugged and sparsely populated terrain.
Document 4: Leh district: Leh is one of the two districts located in Ladakh, the other being the Kargil District to the west, in the state of Jammu and Kashmir, India. With an area of 45,110 "km", it is the second largest district in the country (after Kutch, Gujarat) in terms of area. It is bounded on the north by Ghanche District (Gilgit-Baltistan), a small border with Xinjiang, China, via the Karakoram Pass which is part of the district. Aksai Chin and Tibet are to the east, Kargil district to the west, and Lahul and Spiti to the south. The district headquarters is in Leh. It lies between 32 to 36 degree north latitude and 75 to 80 degree east longitude.
Document 5: Prefecture-level city: A prefectural-level municipality (), prefectural-level city or prefectural city; formerly known as province-controlled city () from 1949 to 1983, is an administrative division of the People's Republic of China (PRC), ranking below a province and above a county in China's administrative structure. Prefectural level cities form the second level of the administrative structure (alongside prefectures, leagues and autonomous prefectures). Administrative chiefs (mayors) of prefectural level cities generally have the same rank as a division chief () of a national ministry. Since the 1980s, most former prefectures have been renamed into prefectural level cities.
Document 6: Nyingchi: Nyingchi also known as Linzhi is a prefecture-level city in southeast of the Tibet Autonomous Region. The administrative seat of Nyingchi is Bayi District. The Chinese claim part of Arunachal Pradesh, which is one of the states of India, as part of the prefecture. (See South Tibet dispute.)
Document 7: Jiangcheng Hani and Yi Autonomous County: Jiangcheng Hani and Yi Autonomous County () is an autonomous county under the jurisdiction of Pu'er City, in southern Yunnan, China, bordering Laos and Vietnam to the south, making it the only county in the province to border more than one country. By road, its seat, the town of Menglie (勐烈镇 ), is 520 km from Kunming and 145 km from Simao District, the municipal seat of Pu'er.
Document 8: Jianghua Yao Autonomous County: Jianghua ( ""Jianghua Yao Autonomous County"", ; usually referred to as ""Jianghua County"", ) is an autonomous county of Yao people in the Province of Hunan, China, it is under the administration of Yongzhou Prefecture-level City.
Document 9: Langfang: Langfang (), is a prefecture-level city of Hebei Province, which was known as Tianjin Prefecture until 1973. Hebei province was renamed Langfang Prefecture after Tianjin became a municipality and finally upgraded into a prefecture-level city in 1988. Langfang is located approximately midway between Beijing and Tianjin. At the 2010 census, the population of Langfang was 4,358,839, of whom 868,066 lived in the built-up ("or metro") area made of Guangyang and Anci districts; its total area is around 6417.28 km² . Langfang borders Baoding to the southwest, Cangzhou to the south (both prefecture-level cities of Hebei), Beijing to the north and Tianjin to the east. Sanhe City and Dachang Hui County are now conurbated with Beijing, so that they form part of the same built-up area. Langfang is the smallest prefecture-level city of Hebei Province by land area.
Document 10: Lancang Lahu Autonomous County: Lancang Lahu Autonomous County () is an autonomous county under the jurisdiction of Pu'er City, in southwestern Yunnan province, China. Lancang is the same as Lan Xang, and refers to the Mekong River (known in Chinese as the Lancang) on its eastern borders and adopted by modern Laos, a Tai word meaning "Million Elephants".
Document 11: Tibet Area (administrative division): The Tibet Area was a province-level administrative division of the Republic of China and early People's Republic of China. The Republic of China never had any real control over the area, which was "de facto" controlled by the Ganden Phodrang government in Lhasa. When the republic was founded in 1912, the Kashag controlled about the same area as the Tibet Area, but later also took control of the western portion of Sikang Province; thus for the most of the Republic of China period, Lhasa controlled an area which was near identical to the contemporary Tibet Autonomous Region. The People's Republic of China invaded Chamdo in 1950 and incorporated the Dalai Lama-controlled regions in 1951. Following the 1959 Tibetan uprising, the State Council of the PRC ordered to replace the Kashag government with the "Preparatory Committee for the Tibet Autonomous Region" which was established in 1956. The current Tibet Autonomous Region was eventually established in 1965.
Document 12: LHA Charitable Trust: Lha Charitable Trust – Institute For Social Work and Education (Lha) is an award-winning, grassroots, nonprofit organization, and one of the largest Tibetan social work organizations based in Dharamsala, India. It is the first organization that was established in exile to develop a primary focus on Tibetan social work. The Lha Charitable Trust was founded in 1997 and is registered as a charitable trust by the Himachal Pradesh government of India. Lha is managed by Tibetan refugees, is supported by volunteers and contributors from around the world, and serves refugees, the local Indian population and people from the surrounding Himalayan region. In a short period of time, the organization "has grown in leaps and bounds, from a small start-up with two computers to one of largest community based Tibetan NGOs in Dharamsala." "Lha" is a sacred Tibetan word that means "superior body" or "energy body", whereby the "Lha body" exists between the physical body and the mind.
Document 13: Hekou North Railway Station: Hekou North Railway Station () is a railway station in Hekou Town, the county seat of Hekou Yao Autonomous County in Yunnan Province of China. It is the southern end of the standard-gauge Kunming–Yuxi–Hekou Railway. It also is connected by meter-gauge tracks to the meter-gauge Kunming–Hekou Railway (the Chinese section of the international Kunming–Hai Phong Railway), thus serving as a linking point between Vietnam's meter-gauge rail network and China's standard-gauge network.
Document 14: Hekou Yao Autonomous County: The Hekou Yao Autonomous County () is an autonomous county in the southern part of the Yunnan province of China. It is part of the Honghe Hani and Yi Autonomous Prefecture and borders the northern Vietnamese town of Lào Cai. It was apparently known as Zhongcheng () during the Tang dynasty.
Document 15: Kangding: Kangding (Chinese) or Dartsedo (Tibetan), is a city and the location of the seat of Garzê Tibetan Autonomous Prefecture in western Sichuan province of Southwest China. Kangding's urban center has around 100,000 inhabitants.
ground_truth: It is part of the Honghe Hani and Yi Autonomous Prefecture and borders the northern Vietnamese town of Lào Cai.