Please, I need help with this exercise asap. I need to find the most cost-efficient solution for the problem. Please explain step by step if possible. Thank you!

Identify the critical path(s). Trim 3 days from the project duration. Which activities should be shortened so that the cost is the lowest? What is the additional cost? Identify the critical path(s). Trim 3 days from the project duration. Which activities should be shortened so that the cost is the lowest? What is the additional cost