Answer: (d) have
Step-by-step explanation:
A helping verb helps a main verb describe an action. This action can be an event that happened in the past, present, or will in the future. Other helping verbs are should, could, and will. Have is a helping verb because it help the main verb in a sentence to complete out a task whenever that may be.
Ex.
James will have to help Mary with her homework tomorrow night.
This sentence shows that James will carry out an action by helping Mary with her homework, by using the word, "have".