Evaluate the following projects based on their cash flows:

Project Alpha:

• Initial investment: $15,000
• Year 1: $4,000
• Year 2: $5,000
• Year 3: $6,000
• Year 4: $7,000

Project Beta:

• Initial investment: $20,000
• Year 1: $6,000
• Year 2: $6,000
• Year 3: $6,000
• Year 4: $6,000

Project Gamma:

• Initial investment: $10,000
• Year 1: $2,000
• Year 2: $3,000
• Year 3: $3,000
• Year 4: $4,000

a) Calculate the NPV of each project at a 12% discount rate. b) Rank the projects based on their NPVs. c) Determine the discounted payback period for each project.