Topic on long term investment decisions $($capital budgeting$)$ and risk & returnCalculation of risk is the most important element of Discounted Cash Flow $($DCF$)$ based investment decisions. In capital budgeting decisions, the risk can also be associated with an individual project. For example, project A may be riskier than Project B$.$ That is a firm can face different types of risks such as:

$$ Financial risk, which is a firm$$s ability to meet its financial obligations,

$$ Business risk, for example, chances of a major shift in the industry, and$/$or technology in the future $($electric and driverless cars!$),$ and

$$ Project specific risk, for example, introducing a new product $($not yet tested in the market$)$ versus enhancing an existing product or implementing a major business transformation for cost reduction $($efficiency$).$

Given these different types of risks do you think it is appropriate to use a single cost of capital, for example, WACC $($Weighted Cost of Capital$)$ to evaluate firm$$s all capital projects for decision making? Or the firm should use multiple $$cost of capital$$ rates according to different risk levels? Please discuss