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.

Passage: For temperature studies, subjects must remain awake but calm and semi-reclined in near darkness while their rectal temperatures are taken continuously. Though variation is great among normal chronotypes, the average human adult's temperature reaches its minimum at about 05:00 (5 a.m.), about two hours before habitual wake time. Baehr et al. found that, in young adults, the daily body temperature minimum occurred at about 04:00 (4 a.m.) for morning types but at about 06:00 (6 a.m.) for evening types. This minimum occurred at approximately the middle of the eight hour sleep period for morning types, but closer to waking in evening types.
What physical factor must be periodicly monitored in temperature studies?

Passage: Since World War II, aircraft carrier designs have increased in size to accommodate a steady increase in aircraft size. The large, modern Nimitz class of US carriers has a displacement nearly four times that of the World War II–era USS Enterprise, yet its complement of aircraft is roughly the same—a consequence of the steadily increasing size and weight of military aircraft over the years. Today's aircraft carriers are so expensive that nations which operate them risk significant political, economic, and military impact if a carrier is lost, or even used in conflict.
Why have aircraft carriers increased in size since World War I?

Passage: Most of the world's airports are owned by local, regional, or national government bodies who then lease the airport to private corporations who oversee the airport's operation. For example, in the United Kingdom the state-owned British Airports Authority originally operated eight of the nation's major commercial airports - it was subsequently privatized in the late 1980s, and following its takeover by the Spanish Ferrovial consortium in 2006, has been further divested and downsized to operating just five. Germany's Frankfurt Airport is managed by the quasi-private firm Fraport. While in India GMR Group operates, through joint ventures, Indira Gandhi International Airport and Rajiv Gandhi International Airport. Bengaluru International Airport and Chhatrapati Shivaji International Airport are controlled by GVK Group. The rest of India's airports are managed by the Airports Authority of India.

When was the Airports Authority of India privatized?