A plumber fixes a leaky pipe in a medical practice late at night on September 23rd. He mails an invoice for services rendered to the medical practice that is received on September 29th and is due by October 14th. A check is written to pay the invoice on October 2nd. Under accrual accounting, what should be the posting date for the repair expense?
a. October 2nd
b. September 23rd
c. September 29th
d. October 14th