Concept:The effective annual rate accounts for compounding within a year, calculated from the nominal rate.Explanation:Let the nominal rate be r=8%=0.08. Compounding semi-annually gives n=2 periods per year. The effective rate formula is: Effective rate=(1+nr)n−1. Substitute: (1+20.08)2−1=(1+0.04)2−1. Calculate: (1.04)2=1.0816, then subtract 1 to get 0.0816. Convert to percentage: 0.0816×100%=8.16%.Answer:The effective rate is 8.16%, which corresponds to option C.