For a multi-product firm, if a project's level of risk differs from that of the overall firm, then the:

a. project should be discounted using the overall firm's beta.

b. project should be discounted at the T-bill rate.

c. CAPM can no longer be used to estimate the cost of equity as beta no longer applies.

d. project should be discounted at the market rate.

e. project should be discounted using a beta commensurate with the project's risks.