Definition: This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
Input: Passage: In 1980, General Secretary and reformist Hu Yaobang visited Tibet and ushered in a period of social, political, and economic liberalization. At the end of the decade, however, analogously to the Tiananmen Square protests of 1989, monks in the Drepung and Sera monasteries started protesting for independence, and so the government halted reforms and started an anti-separatist campaign. Human rights organisations have been critical of the Beijing and Lhasa governments' approach to human rights in the region when cracking down on separatist convulsions that have occurred around monasteries and cities, most recently in the 2008 Tibetan unrest.
Output:
Who visited Tibet in 1989?