Consider a 2 year interest rate swap to pay a fixed interest rate and receive a floating rate. The current 0.5 years , 1 year, 1.5 years, and 2 year spot zero coupon interest rates are 3.90%, 4.00%, 4.10%, and 4.20% respectively, all in annual effective terms. The per annum fixed rate, with semiannual compounding, will be:

a) 4.05%

b) 4.15%

c) 4.20%

d) 4.10%