Assume that stock market retums do follow a single index structure. An investment fund analyzes 300 stocks in order to construct a mean-variance efficient portfolio constrained by 300 investments. They will need to calculate estimates of firm-specific variances and estimate/estimates for the variance of the macroeconomic factor. Select one: O a. 300: 1 O b. 44,859; 300 c. 44.859: 1 d. 1; 300 e. 300: 300 You expect that AT&T stock will offer an expected rate of return of O.14. It has a beta of 1.2. The risk-free rate is 0.05. The market expected rate of return is 0.125. According to the Capital Asset Pricing Model, this security is: Select one: O a overpriced by 2 b.underpriced by 26. c. cannot be determined from the data provided d. fairly priced