The Problem of Using the Overall Firm's Beta in Discounting

The problem of using the overall firm's beta in discounting projects of different risk is the:

A) firm would accept too many high-risk projects.
B) firm would reject too many low risk projects.
C) firm would reject too many high-risk projects.
D) firm would accept too many low risk projects.
E) Both firm would accept too many high-risk projects; and firm would reject too many low risk projects.