Your firm spends $ 510000 per year in regular maintenance of its equipment. Due to the economic​ downturn, the firm considers forgoing these maintenance expenses for the next 3 years. If it does​ so, it expects it will need to spend $ 2.1 million in year 4 replacing failed equipment. a. What is the IRR of the decision to forgo maintenance of the​ equipment? b. Does the IRR rule work for this​ decision? c. For what costs of capital​ (COC) is forgoing maintenance a good​ decision?