Final answer:
The effective annual rate (EAR) when the nominal interest rate is 20% per year and is monthly compounded is 21.94%, which corresponds to option A.
Step-by-step explanation:
If the nominal interest rate (r) is 20% per year and is monthly compounded (n=12), to find the effective annual rate (EAR or a), we use the formula:
EAR = (1 + r/n)^(n) - 1
Where:
r = nominal interest raten = number of compounding periods per year
Substituting the given values:
EAR = (1 + 0.20/12)^(12) - 1
EAR = (1 + 0.01666667)^(12) - 1
EAR = (1.01666667)^(12) - 1
EAR = 1.2194 - 1
EAR = 0.2194, or 21.94%
Therefore, the effective annual rate is 21.94%, corresponding to option A.