15. Which of the following statements is true regarding the optimal risky portfolio:

1. It is designated by the point of tangency with iso-utility curve and the capital allocation line.
2. It is designated by the point of highest Sharpe ratio in the opportunity set.
3. It is designed by the point of tangency with the opportunity set and the securities market line.
4. This portfolio gives the highest standard deviation risk per unit of risk premium in the opportunity set.