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: Early Presbyterians were careful to distinguish between the "church," which referred the members, and the "meeting house," which was the building in which the church met. Until the late 19th century, very few Presbyterians ever referred to their buildings as "churches." Presbyterians believed that meeting-houses (now called churches) are buildings to support the worship of God. The decor in some instances was austere so as not to detract from worship. Early Presbyterian meeting-houses were extremely plain. No stained glass, no elaborate furnishings, and no images were to be found in the meeting-house. The pulpit, often raised so as only to be accessible by a staircase, was the centerpiece of the building.

SOLUTION: What was the building where the images met called?

PROBLEM: Passage: Laemmle, Jr. created a niche for the studio, beginning a series of horror films which extended into the 1940s, affectionately dubbed Universal Horror. Among them are Frankenstein (1931), Dracula ( also in 1931), The Mummy (1932) and The Invisible Man (1933). Other Laemmle productions of this period include Imitation of Life (1934) and My Man Godfrey (1936).

SOLUTION: What began in the 1940s?

PROBLEM: Passage: Meanwhile, Le Verrier by letter urged Berlin Observatory astronomer Johann Gottfried Galle to search with the observatory's refractor. Heinrich d'Arrest, a student at the observatory, suggested to Galle that they could compare a recently drawn chart of the sky in the region of Le Verrier's predicted location with the current sky to seek the displacement characteristic of a planet, as opposed to a fixed star. On the evening of 23 September 1846, the day Galle received the letter, he discovered Neptune within 1° of where Le Verrier had predicted it to be, about 12° from Adams' prediction. Challis later realised that he had observed the planet twice, on 4 and 12 August, but did not recognise it as a planet because he lacked an up-to-date star map and was distracted by his concurrent work on comet observations.

SOLUTION:
Who urged Le Verrier to search with the observatory refractor?