An investment project provides cash inflows of $645 per year for eight years. a. What is the project payback period if the initial cost is $1,800? (Enter O if the project never pays back. Round your answer to 2 decimal places, e.g., 32.16.) b. What is the project payback period if the initial cost is $3,500? (Enter O if the project never pays back. Round your answer to 2 decimal places, e.g., 32.16.) c. What is the project payback period if the initial cost is $5,300? (Enter O if the project never pays back. Round your answer to 2 decimal places, e.g., 32.16.) a. Payback period b. Payback period c. Payback period years years years