Please answer the following question: I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "Artists contributing to this format include mainly soft rock/pop singers such as, Andy Williams, Johnny Mathis, Nana Mouskouri, Celine Dion, Julio Iglesias, Frank Sinatra, Barry Manilow, Engelbert Humperdinck, and Marc Anthony."?
A:
What are two examples of female soft rock/pop singers?