who is or are

[dido4]

Who Mom and Dad at the gate now?
(A) are; talk to (B) is; talking with (C) are; talking to (D) is talking; with

The answer is (C).
Why (B) is not correct?

Thank you.

 

[jutfrank]

The compound subject Mom and Dad is considered plural, so the auxiliary verb must agree (are not is).

 

[emsr2d2]

Who ________ Mom and Dad _________ at the gate now?

(A) are; talk to
(B) is; talking with
(C) are; talking to
(D) is talking; with

The answer is (C).
Why is (B) is not correct?

Thank you.

Note my improvements to the layout above. More importantly, note my correction to the word order of your question.