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: As a uniformed military service, the Army is part of the Department of the Army, which is one of the three military departments of the Department of Defense. The U.S. Army is headed by a civilian senior appointed civil servant, the Secretary of the Army (SECARMY), and by a chief military officer, the Chief of Staff of the Army (CSA) who is also a member of the Joint Chiefs of Staff. In the fiscal year 2016, the projected end strength for the Regular Army (USA) was 475,000 soldiers; the Army National Guard (ARNG) had 342,000 soldiers, and the United States Army Reserve (USAR) had 198,000 soldiers; the combined-component strength of the U.S. Army was 1,015,000 soldiers. As a branch of the armed forces, the mission of the U.S. Army is "to fight and win our Nation's wars, by providing prompt, sustained, land dominance, across the full range of military operations and the spectrum of conflict, in support of combatant commanders." The service participates in conflicts worldwide and is the major ground-based offensive and defensive force.

SOLUTION: How many military departments does the Department of Agriculture have?

PROBLEM: Passage: If the Governor General of Canada is unable to give assent, it can be done by either the Deputy of the Governor General of Canada—the Chief Justice of Canada—or another justice of the Supreme Court of Canada. It is not actually necessary for the governor general to sign a bill passed by a legislature, the signature being merely an attestation. In each case, the parliament must be apprised of the granting of assent before the bill is considered to have become law. Two methods are available: the sovereign's representatives may grant assent in the presence of both houses of parliament; alternatively, each house may be notified separately, usually by the speaker of that house. However, though both houses must be notified on the same day, notice to the House of Commons while it is not in session may be given by way of publishing a special issue of the Journals of the House of Commons, whereas the Senate must be sitting and the governor general's letter read aloud by the speaker.

SOLUTION: It is necessary for the governor general to sign what?

PROBLEM: Passage: The term "push-pull" was established in 1987 as an approach for integrated pest management (IPM). This strategy uses a mixture of behavior-modifying stimuli to manipulate the distribution and abundance of insects. "Push" means the insects are repelled or deterred away from whatever resource that is being protected. "Pull" means that certain stimuli (semiochemical stimuli, pheromones, food additives, visual stimuli, genetically altered plants, etc.) are used to attract pests to trap crops where they will be killed. There are numerous different components involved in order to implement a Push-Pull Strategy in IPM.

SOLUTION:
When was the term semiochemcial stimuli established?