Governments can affect a firm's costs by imposing (or not) a variety of taxes. Evaluate the impact of the following taxes on a firm's average (both fixed and variable) and marginal costs in both the short and long run:

a) A tax on income earned from interest.

b) A tax deduction for the depreciation of capital.

c) A tax credit for research and development activity.

d) A tax on the use of capital.

e) A tax on each unit of output produced.