Consider the following projects with respective cash flows:

• Project X: Initial investment of ₹9,000, with returns of ₹2,000, ₹3,000, ₹4,000, and ₹5,000 over the next four years.
• Project Y: Initial investment of ₹11,000, with returns of ₹3,000, ₹3,500, ₹4,000, and ₹6,000.
• Project Z: Initial investment of ₹7,000, with returns of ₹2,000, ₹2,500, ₹3,000, and ₹3,500.

Required:

1. Calculate the payback period for each project.
2. Determine which project meets a standard payback period of 3 years.
3. Compute the NPV for each project at a 12% discount rate.
4. Calculate the IRR for each project.
5. Discuss the projects based on both NPV and IRR criteria.