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: In the late 13th and early 14th centuries, a process took place primarily in Italy but partly also in the Empire that historians have termed a 'commercial revolution'. Among the innovations of the period were new forms of partnership and the issuing of insurance, both of which contributed to reducing the risk of commercial ventures; the bill of exchange and other forms of credit that circumvented the canonical laws for gentiles against usury, and eliminated the dangers of carrying bullion; and new forms of accounting, in particular double-entry bookkeeping, which allowed for better oversight and accuracy.
What old form of accounting was created during the late 13th and early 14th centuries?