instruction:
In this task, you're given an ambiguous question (which can be answered in more than one way). Your task is to write a question that clarifies the given question in such a way that the generated question has one unique answer.
question:
What is the most northerly town in the world?
answer:
What is the most northerly inhabited place in the world?


question:
When did a/c first appear in homes?
answer:
When did the first a/c unit appear in a home?


question:
When did the cross become a symbol of christianity?
answer:

When did the cross become a symbol of christianity that was used reluctantly?