I need formulas please:

Problem 1 (14 points) Compare the following alternatives using an interest rate of 12% compounded monthly answering the following questions, Project C can be replaced with a similar item with the same cash flows every 10 years: Project C $80,000 1,500 Project D $70,000 2,000 Initial cost Monthly O&M costs Salvage value Useful life (years) 1,000 10 a. What is the decision criterion? (2 pts) b. Choose the best project. (8 pts) Bonus: What is the effective annual interest rate? (3 pts) Remember to clearly show the cash flow diagram(s) and the necessary equivalent model(s). (4 pts)