Answer:
11.77%
Explanation:
total investment = $200,000 + $300,000 + $500,000 + $1,000,000 = $2,000,000
stock   weight                     beta       total
A Â Â Â Â Â $200,000 / $2,000,000 Â Â Â Â Â Â 1.5 Â Â Â Â Â Â Â 0.15
B Â Â Â Â Â $300,000 / $2,000,000 Â Â Â Â Â Â -0.5 Â Â Â Â Â Â -0.075
C Â Â Â Â Â $500,000 / $2,000,000 Â Â Â Â Â Â 1.25 Â Â Â Â Â Â 0.3125
D Â Â Â Â Â $1,000,000 / $2,000,000 Â Â Â Â Â 0.75 Â Â Â Â Â 0.375
Portfolio                                    0.7625
required rate of return = Rf + beta(Rm - Rf) = 7% + 0.7625(13.25% - 7%) = 11.7656% = 11.77%