The efficient frontier of risky assets is A. the portion of the investment opportunity set that lies above the global minimum variance portfolio.
B. the portion of the investment opportunity set that represents the highest standard deviations.
C. the portion of the investment opportunity set that includes the portfolios with the lowest standard deviation.
D. the set of portfolios that have zero standard deviation

A. the portion of the investment opportunity set that lies above the global minimum variance portfolio.

Explanation:

The Efficient frontier refers to the portfolios set that involves that expected return whose return is high at the level of minimum risk so the asset that contains the high risk profile that investment opportunity set portion should be above the variance portfolio i.e. minimum globally

Therefore the correct option is a.

answer; i believe that the correct answer is (d); the business benefits because owners can share responsibilities;