A company is evaluating two projects, C and D. Project C requires an initial investment of $1,000 and will return $600 per year for 3 years. Project D requires an investment of $1,200 and will return $500, $700, and $800 over the next 3 years.

1. Calculate the net present value (NPV) for each project at a discount rate of 10%.
2. Determine the internal rate of return (IRR) for each project.
3. Discuss which project should be chosen based on NPV and IRR.
4. Illustrate the payback period for both projects.