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.
Q: Passage: Despite the large number of philosophical schools and subtle nuances between many, all philosophies are said to fall into one of two primary categories, which are defined in contrast to each other: Idealism, and materialism.[a] The basic proposition of these two categories pertains to the nature of reality, and the primary distinction between them is the way they answer two fundamental questions: "what does reality consist of?" and "how does it originate?" To idealists, spirit or mind or the objects of mind (ideas) are primary, and matter secondary. To materialists, matter is primary, and mind or spirit or ideas are secondary, the product of matter acting upon matter.
A:
What is the last question to ask in order to define the two classes?