Pls explain and answer fully. Pls answer if you know 100% the answer is correct.

3. (20 points) A portfolio manager has the following risk-return information of three securities: Portfolio Stock X Stock Y Risk-free Forecasted Return 20% 15% 5% Standard Deviation 30% 25% 0% If the manager is only able to invest in one and only one stock between X and Y, which stock should she/he choose? Explain your answers