Which of the following would be a good clincher sentence for a cause-and-effect paragraph that begins with this topic sentence?
Tom's improved singing ability came as a result of three factors.

A.
Those three things have turned Tom's voice from a chirp to a chorus.

B.
Tom's ability to sing caused some major changes in his life.

C.
Tom's improved singing ability came as a result of three factors.

D.
And not only does Tom sing well, but he's also a smash on the drums.