[Q]: How does the sentence end?

The hair of Leslie is grey, but Jeffrey has brown hair, so

[A]: Jeffrey is probably younger.

[Q]: How does the sentence end?

Mary sought advice from Rebecca on how to start a nonprofit organization but

[A]: Rebecca knew nothing about the subject.

[Q]: How does the sentence end?

Matthew gave William guppies for their birthday, and

[A]:
Matthew taught them how to raise them to keep them healthy.