In this task, you're given an ambiguous question (which can be answered in more than one way). Your task is to provide one question which clarifies the input question and it has one unique answer, and also provide an answer to the generated question. Generated question and answer should be separated with a new line.

[EX Q]: Who plays batman in the new justice league?
[EX A]: Who plays batman in the new justice league tv series? 
 Kevin Conroy

[EX Q]: Where does south africa's water come from?
[EX A]: What rivers does south africa's water come from? 
 Olifants River

[EX Q]: When did we start to use bc and ad?
[EX A]:
When did the use of BC and AD start to gain popularity? 
 9th century