A firm has determined its cost of each source of capital and optimal capital structure, which is composed of the following sources and target market value proportions:

Source of Capital	Target Market Proportions	After-Tax Cost
Long-term debt	40%	6%
Preferred stock	10	11
Common stock equity	50	15

The weighted average cost of capital is

A. 11 percent.
B. 6 percent.
C. 15 percent.
D. 10.7 percent.