The WACC is calculated using the cost of debt, cost of equity, and cost of preferred stock, weighted by their respective proportions in the capital structure. Retained earnings are not a source of external financing and therefore not included in the WACC calculation.

The net present value (NPV) method is a capital budgeting technique that takes into account the time value of money by discounting future cash flows back to the present. A project with a positive NPV is considered profitable.

The opportunity cost of a project is the value of the next best alternative project that is sacrificed when choosing to undertake the current project. It represents the potential收益 that could have been earned from the foregone project.

The cost of equity is primarily determined by the risk-free rate, market risk premium, and the company's beta. The debt-to-equity ratio is a measure of a company's financial leverage and does not directly impact the cost of equity.

The internal rate of return (IRR) is the discount rate that makes the net present value (NPV) of a project equal to zero. It is used to determine the project's profitability and compare it with other investment opportunities.

Business risk is not a type of capital budgeting risk. It is a general term that refers to the risk associated with the overall operations and performance of a company. Capital budgeting risks are specific to the evaluation and selection of investment projects.

The payback period is calculated by dividing the initial investment of a project by the average annual cash flow generated by the project. It measures the time it takes for the project to generate enough cash flow to cover the initial investment.

The net present value (NPV) method is most appropriate for projects with uneven cash flows because it takes into account the time value of money and discounts future cash flows back to the present. This allows for a more accurate assessment of the project's profitability.

The relationship between the cost of capital and WACC depends on the project's risk. For projects with higher risk, the cost of capital will be higher than the WACC. Conversely, for projects with lower risk, the cost of capital will be lower than the WACC.

Retained earnings are not a component of a project's cash flow statement. They are a part of the company's financial statements and represent the portion of earnings that are retained by the company rather than distributed as dividends to shareholders.

The profitability index is calculated by dividing the present value of future cash flows generated by a project by the initial investment. It is used to assess the project's profitability and compare it with other investment opportunities.

The net present value (NPV) method is most appropriate for projects with a long payback period because it takes into account the time value of money and discounts future cash flows back to the present. This allows for a more accurate assessment of the project's profitability over its entire life.

The weighted average cost of capital (WACC) is calculated to determine the project's cost of capital, which is the minimum rate of return that the project must generate in order to break even.

Business risk is not a type of financial risk in capital budgeting. It is a general term that refers to the risk associated with the overall operations and performance of a company. Financial risks are specific to the financing and investment decisions of a company.