The weighted average cost of capital (wacc) is:
a) the required rate of return for all of a firm's capital investment projects.
b) the required rate of return for a firm's average risk projects.
c) not applicable for use by mne.
d) equal to 13%.

a) the required rate of return for all of a firm's capital investment projects.

Explanation:

The weighted average cost of capital refers to the blended cost of capital of a firm from all its sources. It is the proportionate representation of a firm's cost of capital from its various sources. A firm's sources of capital include bonds, common stock, preferred stocks, and other long term sources of are factored in WACC.

In calculating the WACC, each source of capital is proportionately weighted according to its percentage contribution to capital.  The WACC is applied in capital budgeting as a firm preferred discount rate when calculating the net present value.

3rd the reason why is because of management and leadership