Adam received a bonus of $5,000 from his employer. Which one of the following federal income withholding tax amounts is not in accordance with IRS rules regarding supplemental wage payments? Adam earns biweekly wages of $4,000, is single, and claims one allowance. Assume his employer uses the percentage method of withholding.

a. $1,441.39 on his bonus if taxes had already been withheld from his regular pay.

b. $1,575.84 if his bonus and wages are paid on different dates within the pay period.

c. $1,767.92 if his bonus is taxed at the supplemental wage percentage and added to his regular wages paid in the same period.

d. $2,109.31 if his bonus and wages are paid at the same time during the pay period.