Answer: I think the answer is B.
Explanation:
because everyone is a subject and sing is a verb
The simple predicate is "are interested".
D. The first African American opera singer that permanently became a member of New York's Metropolitan Opera was Marian Anderson. She is a contralto who became one of the best singers during the 20th century. A lot of people say that she has a very rich voice indeed. She was also offered with various opportunities such as acting but declined the offer due to her lack of knowledge in the field of acting. She is also the inspiration of the many black artists that want to excel greatly despite if the racial discrimination that they experienced back then.
