Weighted average cost of debt, preferred stock and common equity is classified as

cost of salvage
cost of interest
cost of taxation
cost of capital

The correct answer is D. cost of capital.

The weighted average cost of capital (WACC) is a measure of a company’s overall cost of capital, taking into account the different types of financing it uses. It is calculated by weighting the cost of each type of financing by its proportion of the total capital structure.

The cost of debt is the interest rate that a company pays on its loans. The cost of preferred stock is the dividend rate that a company pays on its preferred shares. The cost of common equity is the return that shareholders expect to earn on their investment in the company.

The WACC is used to calculate the discount rate for a company’s cash flows in a discounted cash flow (DCF) analysis. The DCF analysis is used to estimate the value of a company.

Option A, cost of salvage, is the estimated value of a company’s assets after they have been used up. Option B, cost of interest, is the interest rate that a company pays on its loans. Option C, cost of taxation, is the amount of tax that a company pays on its income.

These are all important concepts in finance, but they are not the same as the WACC.