Janko Wellspring Inc. has a pump with a book value of $35,000 and a 4-year remaining life. A new, more efficient pump, is available at a cost of $56,000. Janko can also receive $9,100 for trading in the old pump. The new pump will reduce variable costs by $13,100 per year over its four-year life. The costs not relevant to the decision of whether or not to replace the pump are:

• $52,400.

• $9,100.

• $13,100.

• $35,000.

• $18,200.