Murphy is a self-employed plumber. He does not maintain an inventory of items used and sold to customers. He purchases items needed for each specific job and adds the amount to the invoice he provides to the customer. How will Murphy report the items purchased on his Schedule C? 

a. He will keep track of all items purchased and claim them as cost of goods sold.

b. He will not claim them as cost of goods sold, and will claim them as supplies.

c. He must itemize each item and can deduct them only when invoices are paid.

d. He will include them in sales tax and not report them on the return