Answer:
C. A risk averse investor would choose the economy in which stock returns are independent because risk can be diversified away in a large portfolio.
Step-by-step explanation:
if stock prices move together, (positive correlation), the volatility of the portfolio will be higher. Higher volatility means higher risk. This is the case with the first economy.
In the second economy however, the stocks are independent of each other meaning there is zero correlation between stocks and hence the portfolio volatility will be much lesser.
As a risk-averse investor you will prefer the portfolio with lower volatility for the same expected return.