If a firm uses it's WACC as the discount rate for all of the projects it undertakes then the firm will tend to: I. reject some positive net present value projects II. accept some negative net present value projects III. favor high risk projects over low risk projects IV. increase it's overall level of risk over time. A. I and III only B. III and IV only C. I, II, and III only D. I, II, and IV only E. I, II, III, and IV