Answer:
The beta of stock A cannot be determined with the given information.
Beta is a measure of systematic risk that compares the volatility of a stock's returns to the overall market's returns. It is calculated by regressing the returns of the stock against the returns of the market. In this case, we have the returns of stock A and the returns of the market, but we do not have the covariance between the two, which is needed to calculate beta.
Therefore, we cannot determine the beta of stock A with the given information.