how to solve this

Suppose you have $1000 to spend on things that you want to buy, and the following four things cost exactly $1000 per unit and give you the following values: i) a textbook, value = $1500 ii) a laptop, value = $2000 iii) a jacket, value = $1600 iv) a wallet, value = $700 Based on this information, a. which activity has the lowest opportunity cost? b. which activities have the same opportunity cost? c. what is the best use of your money using the marginal benefit and marginal cost concepts? d. what is the other thing that could affect the opportunity cost in this example