Answer:
D) Sell - because differential income is $1,500 if Bulls sells rather than leases
Explanation:
Differential revenues and costs equal the difference in revenues or costs resulting from choosing one alternative course of action. This concept is very similar to opportunity costs analysis, since it compares what would happen if one decision is taken versus taking another alternative decision.
If Bull sells the machine, they will receive = $90,000 - 5% = $85,500
If Bulls lease the machine, they will receive = ($24,000 - $3,000) x 4 years = $84,000
Differential revenue = $85,500 - $84,000 = $1,500