Answer: The answer is Main verb
Step-by-step explanation:
Main verbs are often assisted by auxiliary (or “helper”) verbs. These verbs help show when in time events are happening.
For example, in the sentence “Brian was eating a pizza,” the auxiliary verb “was” shows Brian eating a pizza in the past.
Other auxiliary verbs: is, has, has been, had been. Auxiliary verbs always appear along with their main verbs, for example, He is going.
so that's why the answer is main verb