Answer:
A. auxiliary verb
Explanation:
Auxiliary verb helps express a meaning that one verb alone could not.
Generally, auxiliary verbs are verbs that can be used to depict grammatical or functional meaning that cannot be expressed by a single verb. Thus, an auxiliary verb is used to express a verb's tense, voice, mood or modality, aspect and emphasis.
Some examples of an auxiliary verb are have, can, will, may, shall, be, must, do, might, could etc.
For instance, "have" in the statement "I have finished my homework."
