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: Conventional ("tailhook") aircraft rely upon a landing signal officer (LSO, radio call sign paddles) to monitor the aircraft's approach, visually gauge glideslope, attitude, and airspeed, and transmit that data to the pilot. Before the angled deck emerged in the 1950s, LSOs used colored paddles to signal corrections to the pilot (hence the nickname). From the late 1950s onward, visual landing aids such as Optical Landing System have provided information on proper glide slope, but LSOs still transmit voice calls to approaching pilots by radio.

SOLUTION: What does OSL stand for?

PROBLEM: Passage: Uranium carbides and uranium nitrides are both relatively inert semimetallic compounds that are minimally soluble in acids, react with water, and can ignite in air to form U
3O
8. Carbides of uranium include uranium monocarbide (UC), uranium dicarbide (UC
2), and diuranium tricarbide (U
2C
3). Both UC and UC
2 are formed by adding carbon to molten uranium or by exposing the metal to carbon monoxide at high temperatures. Stable below 1800 C, U
2C
3 is prepared by subjecting a heated mixture of UC and UC
2 to mechanical stress. Uranium nitrides obtained by direct exposure of the metal to nitrogen include uranium mononitride (UN), uranium dinitride (UN
2), and diuranium trinitride (U
2N
3).

SOLUTION: Along with uranium monocarbide and uranium dicarbide, what is a unnotable carbide of uranium?

PROBLEM: Passage: The polyphony of Christian a cappella music began to develop in Europe around the late 15th century, with compositions by Josquin des Prez. The early a cappella polyphonies may have had an accompanying instrument, although this instrument would merely double the singers' parts and was not independent. By the 16th century, a cappella polyphony had further developed, but gradually, the cantata began to take the place of a cappella forms. 16th century a cappella polyphony, nonetheless, continued to influence church composers throughout this period and to the present day. Recent evidence has shown that some of the early pieces by Palestrina, such as what was written for the Sistine Chapel was intended to be accompanied by an organ "doubling" some or all of the voices. Such is seen in the life of Palestrina becoming a major influence on Bach, most notably in the aforementioned Mass in B Minor. Other composers that utilized the a cappella style, if only for the occasional piece, were Claudio Monteverdi and his masterpiece, Lagrime d'amante al sepolcro dell'amata (A lover's tears at his beloved's grave), which was composed in 1610, and Andrea Gabrieli when upon his death it was discovered many choral pieces, one of which was in the unaccompanied style. Learning from the preceding two composeres, Heinrich Schutz utilized the a cappella style in numerous pieces, chief among these were the pieces in the oratorio style, which were traditionally performed during the Easter week and dealt with the religious subject matter of that week, such as Christ's suffering and the Passion. Five of Schutz's Historien were Easter pieces, and of these the latter three, which dealt with the passion from three different viewpoints, those of Matthew, Luke and John, were all done a cappella style. This was a near requirement for this type of piece, and the parts of the crowd were sung while the solo parts which were the quoted parts from either Christ or the authors were performed in a plainchant.

SOLUTION:
What began to develop in Europe during the 1500"s