Assume a Firm Has an Ongoing Need for a Machine,and

Assume a firm has an ongoing need for a machine,and the current machine is operating efficiently.The firm should plan to replace this machine when it

A) reaches the end of its depreciable life.
B) is fully paid for.
C) reaches a point where the book value is less than half of the original cost.
D) can be replaced with a machine that has a lower equivalent annual cost.
E) can be sold at a price that exceeds the current book value.