Answer:
The Square Box should accept Project B only
Explanation:
Square Box should decide the project whose Net present value (NPV) of future cash inflow is higher than the initial cost of investment
NPV of cash inflow from Project A = 3,000/(1+12%)+7,000/(1+12%)^2+10,000/(1+12%)^3 = $15,377, lower then initial cost of $18,000 → deny Project A
NPV of cash inflow from Project B = 3,000/(1+12%)+7,000/(1+12%)^2+15,000/(1+12%)^3 = $18,936, higher then initial cost of $18,000 → accept Project B