Final answer:
To calculate the interest earned at 1.2% compounded monthly for three years, we use the formula for compound interest. However, since the principal amount is not given, the interest earned varies based on the principal amount.
Step-by-step explanation:
To calculate the interest earned at 1.2% compounded monthly for three years, we can use the formula for compound interest:
A = P(1 + r/n)^(nt)
Where:
A = the final amount
P = the principal amount
r = the interest rate (as a decimal)
n = the number of times interest is compounded per year
t = the number of years
In this case, the principal amount is not given, so we cannot determine the exact amount of interest earned. Therefore, the answer is: a. Varies based on principal amount.