Answer: E. Yes, because income will increase by $3,000 in total.
Explanation:
If the Incremental benefit is positive then the pump should be replaced.
Incremental Benefit = Cost saving + cash received for trading in old pump - Cost of new pump
= (10,000 * 4) + 8,000 - 45,000
= $3,000
Over the four years, the income from the decision to replace the old pump will yield an income of $3,000.