A program contains a method with the header num calculateTaxes$($num amount, string name$).$ Which of the following methods can coexist in the same program with no possible ambiguity?

a$.$ num calculateTaxes$($string name, num amount$)$

b$.$ string calculateTaxes$($num money, string taxpayer$)$

c$.$ num calculateTaxes$($num annualPay, string taxpayerId$)$

d$.$ void calculateTaxes$($num gross, string ssn$)$