Assume the following utility function U = (q × M)/100. Importantly, q represents the fish population (numbers), and M represents income (tens of thousands of yen, M = 100).

a. State the WTP amount when fish populations increase from 10 to 20.

b. Assume the fish population decreases from 10 to 2 due to river pollution.

State how much the WTP is in order to preserve the current fish population level at 10.

c. There is a preservation policy in place to increase the fish population levels from 10 to 20, but it is cancelled. State how much the WTA compensation is in such a scenario.