Indicate which of the following errors, each considered individually, would cause the trial balance totals to be unequal:

a. A fee of $21,000 earned and due from a client was not debited to Accounts Receivable or credited to a revenue account, because the cash had not been received.

b. A receipt of $11,300 from an account receivable was journalized and posted as a debit of $11,300 to Cash and a credit of $11,300 to Fees Earned.

c. A payment of $4,950 to a creditor was posted as a debit of $4,950 to Accounts Payable and a debit of $4,950 to Cash.

d. A payment of $5,000 for equipment purchased was posted as a debit of $500 to Equipment and a credit of $500 to Cash.

e. Payment of a cash withdrawal of $19,000 was journalized and posted as a debit of $1,900 to Salary Expense and a credit of $19,000 to Cash. Indicate which of the preceding errors would require a correcting entry.