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.
Input: Passage: Smyth, convinced that his self-baptism was invalid, applied with the Mennonites for membership. He died while waiting for membership, and some of his followers became Mennonites. Thomas Helwys and others kept their baptism and their Baptist commitments. The modern Baptist denomination is an outgrowth of Smyth's movement. Baptists rejected the name Anabaptist when they were called that by opponents in derision. McBeth writes that as late as the 18th century, many Baptists referred to themselves as "the Christians commonlythough falselycalled Anabaptists."
Output:
Who thought their self-baptism was valid?