The withholding allowance is used by a person to pay less amount of tax on his or her income to government.Neither we should use too many allowance nor very little. if we use too many allowance , and at the end of year getting caught or any mismatch happens we have to pay penalty for that and Definitely we should use adequate amount of allowance so that we don't have to pay too much tax to the government.
Gross biweekly earnings of Mario= $ 784.21
Amount that Mario takes his home when he use 1 more withholding allowance= $ 13= Amount exempted from tax
It is given that Mario has taken 1 more withholding allowance to pay tax less by amount of $13.So he must have possessed atleast 1 allowance previously and added 1 more.
So , minimum number of allowance possessed by Mario= 2
Correct option should be (a): 3