Which of the following must use the accrual method of accounting?

I. A property management company, operating as a C corporation, with average annual gross receipts of $50 million.

II. An incorporated law firm with average annual gross receipts of $6 million.

III. An unincorporated grocery store with average annual gross receipts of $1,200,000.

a. All of these choices must use the accrual method.

b. None of these choices must use the accrual method.

c. Only I and III must use the accrual method.

d. Only I and II must use the accrual method.

e. Only III must use the accrual method.