Hey Patricia, I hope you're having a good weekend. General rule with short answer questions: Try to use the same verb. For example, Do you live in Hawaii? No, I don't. We usually apply this "mirroring" to pronouns too. So the question "Is he your friend?" Would be answered with "Yes, he is." The question " Is THAT your friend?", however, is answered with "It is" or "It isn't". But remember, THAT would only be used if we're pointing to someone far away. We wouldn't call someone standing right next to us "That", it would be "This". For example... "Oh, is this your new boyfriend!?" "It is! Sarah, let me introduce Jim". Hope this helps :)

B. No, she/he isn't.