TASK 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.
PROBLEM: Passage: On April 12, 1980, a military coup led by Master Sergeant Samuel Doe of the Krahn ethnic group overthrew and killed President William R. Tolbert, Jr.. Doe and the other plotters later executed a majority of Tolbert's cabinet and other Americo-Liberian government officials and True Whig Party members. The coup leaders formed the People's Redemption Council (PRC) to govern the country. A strategic Cold War ally of the West, Doe received significant financial backing from the United States while critics condemned the PRC for corruption and political repression.

SOLUTION: Who led a military coup that killed the American ambassador?

PROBLEM: Passage: Mali lies in the torrid zone and is among the hottest countries in the world. The thermal equator, which matches the hottest spots year-round on the planet based on the mean daily annual temperature, crosses the country. Most of Mali receives negligible rainfall and droughts are very frequent. Late June to early December is the rainy season in the southernmost area. During this time, flooding of the Niger River is common, creating the Inner Niger Delta. The vast northern desert part of Mali has a hot desert climate (Köppen climate classification (BWh) with long, extremely hot summers and scarce rainfall which decreases northwards. The central area has a hot semi-arid climate (Köppen climate classification (BSh) with very high temperatures year-round, a long, intense dry season and a brief, irregular rainy season. The little southern band possesses a tropical wet and dry climate (Köppen climate classification (Aw) very high temperatures year-round with a dry season and a rainy season.

SOLUTION: What is in the tropical zone?

PROBLEM: Passage: The botanical term "Angiosperm", from the Ancient Greek αγγείον, angeíon (bottle, vessel) and σπέρμα, (seed), was coined in the form Angiospermae by Paul Hermann in 1690, as the name of one of his primary divisions of the plant kingdom. This included flowering plants possessing seeds enclosed in capsules, distinguished from his Gymnospermae, or flowering plants with achenial or schizo-carpic fruits, the whole fruit or each of its pieces being here regarded as a seed and naked. The term and its antonym were maintained by Carl Linnaeus with the same sense, but with restricted application, in the names of the orders of his class Didynamia. Its use with any approach to its modern scope became possible only after 1827, when Robert Brown established the existence of truly naked ovules in the Cycadeae and Coniferae, and applied to them the name Gymnosperms.[citation needed] From that time onward, as long as these Gymnosperms were, as was usual, reckoned as dicotyledonous flowering plants, the term Angiosperm was used antithetically by botanical writers, with varying scope, as a group-name for other dicotyledonous plants.

SOLUTION:
Who coined the term dicotyledonous?