Which of the folloiwng is correct?

In the Treynor-Black model, Multiple Choice portfolio weights are sensitive to large alpha values, which can lead to infeasible long or short positions for many portfolio managers. portfolio weights are not sensitive to large alpha values, which can lead to infeasible long or short positions for many portfolio managers. portfolio weights are sensitive to large alpha values, which can lead to the optimal portfolio for most portfolio manage portfolio weights are not sensitive to large alpha values, which can lead to the optimal portfolio for most portfolio managers