Answer:
C) Barb will earn interest on interest.
Explanation:
Compound interest can be defined as more interest earned by previously earned interest, i.e. interest that earns more interest.
At the end of the first year both Andy and Barb will have $3,150 in their accounts (= $3,000 + 5%). Since Andy will withdraw his money at the end of year 1, only Barb will earn compound interest. At the end of second year Andy will have $3,150 while Barb will have $3,307.50 (= $3,150 + 5%).