Please answer all question parts and with the correct numbers!

PROBLEM 2: You are looking at juniper control options for rangeland your agency manages. You would like to keep the stocking level at approximately 46 trees per acre. You have been given three different options, burning, chaining, and grubbing. All options would begin in year 1 (with payment due at the end of the year). Your agency uses a discount rate of 4% (annual). 2a) Burning would cost $4/acre and need to be done every 5 years. What is the present value of this option in perpetuity? 2b) Chaining would cost $17/acre and need to be done every 15 years. What is the present value of this option in perpetuity? 2c) Grubbing would cost $7/acre and need to be done every 8 years. What is the present value of this option in perpetuity? 2d) You decide to go with grubbing. What is the opportunity cost of this decision