Question

Read the sentence.

Answer 1

The answer is D. going 

Answer 2

The answer to your question would be that the main verb in the underlined verb phrase is the following one: Going. That is, the correct option would be D.

The main verb is the important verb in the sentence; the one that typically shows the action or state of being of the subject. Main verbs can stand alone or they can be used with an auxiliary verb, just as in the example with will.