This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: The Russians sent a fleet to Sinop in northern Anatolia. In the Battle of Sinop on 30 November 1853 they destroyed a patrol squadron of Ottoman frigates and corvettes while they were anchored in port. Public opinion in the UK and France was outraged and demanded war. Sinop provided the United Kingdom and France with the casus belli ("cause for war") for declaring war against Russia. On 28 March 1854, after Russia ignored an Anglo-French ultimatum to withdraw from the Danubian Principalities, the UK and France formally declared war. Question: While anchored in the port, what did the Russians destroy?
a patrol squadron of Ottoman frigates and corvettes

Passage: On 30 September, Zhou Enlai warned the United States that China was prepared to intervene in Korea if the United States crossed the 38th parallel. Zhou attempted to advise North Korean commanders on how to conduct a general withdrawal by using the same tactics which had allowed Chinese communist forces to successfully escape Chiang Kai-shek's Encirclement Campaigns in the 1930s, but by some accounts North Korean commanders did not utilize these tactics effectively. Historian Bruce Cumings argues, however, the KPA's rapid withdrawal was strategic, with troops melting into the mountains from where they could launch guerrilla raids on the UN forces spread out on the coasts. Question: Who vowed to intervene if the US was to engage in conflict North of the 38th parallel?
China

Passage: The Gurjar Pratihar Empire acted as a barrier for Arab invaders from the 8th to the 11th century. The chief accomplishment of the Gurjara Pratihara empire lies in its successful resistance to foreign invasions from the west, starting in the days of Junaid. Historian R. C. Majumdar says that this was openly acknowledged by the Arab writers. He further notes that historians of India have wondered at the slow progress of Muslim invaders in India, as compared with their rapid advance in other parts of the world. Now there seems little doubt that it was the power of the Gurjara Pratihara army that effectively barred the progress of the Arabs beyond the confines of Sindh, their first conquest for nearly 300 years. Question: What was the most notable accomplishment of the Gurjara Pratihara Empire?

its successful resistance to foreign invasions