To summarize everything, the following are the deductible computation: Social Sec. Tax: 6.2% = 50.22 Medicare tax : 1.45% = 11.745 State tax: 21% of 3 = 0.63% = 5.103 ------------------------------------------------- Total of : 67.068 deducted amount of his gross pay = 742.932 (3 federal withholding) For the 4 with holding allowance would be: State tax: 21% 4= 0.84 % = 6.8704 Base on the computation, the possible answer amoung them would be C. increase by $18.15