During Your Service Call at the Residence of a Customer

Multiple Choice

During your service call at the residence of a customer, you discover you will need a part that you don't currently have.   
What should you do in this case?

A) Leave and get the part and come back.
B) Tell the customer to purchase the part and call when she receives it.
C) Explain the situation and give the customer options on how to order the part and when you will return to complete the repair.
D) Tell the customer you need the part, do research on the part, and schedule a time to come back and fix the computer.