4. An investor would like to construct his complete portfolio by allocating funds between the risk-free asset and a risky portfolio that has an expected return of 15% and standard deviation of 25%. The risk free rate is 5%. Which of the following complete portfolios can this investor achieve?A. Portfolio A with E(R)=17.5% and STD=25%B. Portfolio A with E(R)=20% and STD=37.5%C. Portfolio B with E(R)=13% and STD=16%D. Portfolio C with E(R)=10% and STD=20%