Detailed Instructions: You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.
Q: Category: POP SINGERS 
Clue: Charting her 18th No. 1 single in April 2008, she now has more Billboard No. 1 pop hits than any other solo artist
A:
mariah carey