In calculating the WACC, it's most appropriate to use:

A) market values for structure and component costs because the best reflect next year's capital costs which will be encountered when money is raised for future projects.
B) book values for structure and component costs because these reflect the actual existing capital structure and what the firm really pays for the capital it has.
C) the target structure because it's in some sense the best.
D) market values for structure and target values for costs because they're the most practical.

Market values for structure and component costs should be used for calculating the WACC because they reflect the current market perception of the value of the company and its assets, which is used to determine the cost of capital. Book values may not accurately reflect the current market value of the company's assets and liabilities, and the target structure may not necessarily reflect the current market conditions. Using market values provides a more accurate representation of the cost of capital and allows for better decision-making when it comes to financing future projects.