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: The Gregorian calendar is a solar calendar. A regular Gregorian year consists of 365 days, but as in the Julian calendar, in a leap year, a leap day is added to February. In the Julian calendar a leap year occurs every 4 years, but the Gregorian calendar omits 3 leap days every 400 years. In the Julian calendar, this leap day was inserted by doubling 24 February, and the Gregorian reform did not change the date of the leap day. In the modern period, it has become customary to number the days from the beginning of the month, and February 29th is often considered as the leap day. Some churches, notably the Roman Catholic Church, delay February festivals after the 23rd by one day in leap years.

SOLUTION: What calendar is a lunar calendar?

PROBLEM: Passage: In March 1968, CBS and Sony formed CBS/Sony Records, a Japanese business joint venture. With Sony being one of the developers behind the compact disc digital music media, a compact disc production plant was constructed in Japan under the joint venture, allowing CBS to begin supplying some of the first compact disc releases for the American market in 1983.

SOLUTION: In March 1988, CBS and Sony formed what group?

PROBLEM: Passage: The TCM Vault Collection consists of several different DVD collections of rare classic films that have been licensed, remastered and released by Turner Classic Movies (through corporate sister Warner Home Video). These boxed set releases are of films by notable actors, directors or studios that were previously unreleased on DVD or VHS. The sets often include bonus discs including documentaries and shorts from the TCM library. The initial batch of DVDs are printed in limited quantities and subsequent batches are made-on-demand (MOD).

SOLUTION:
Through what company is the MOD released?