Which of the following statements is most correct? O In the Treynor-Black model, the active portfolio only includes exposure to stocks with zero alpha O In the Treynor-Black model, the active portfolio only includes exposure to stocks with positive alpha In the Treynor-Black model, the active portfolio has exposure to stocks with positive and negative alpha In the Treynor-Black model, the active portfolio only includes exposure to stocks with negative alpha In the Treynor-Black model, the active portfolio only includes exposure to stocks with positive beta