Calculate the convexity (measured in six-monthly periods) for a coupon-paying bond maturing in two years, where the bond has a face value of $100 000, yield of 5% p.a. and coupon rate of 7% p.a. Assume interest rates are paid half yearly and the last coupon payment has just been made.

A. 1.85

B. 3.66

C. 9.35

D. 10.26