Solve the linear programming problem using the simplex method.
Maximize $P = 4x_1 + 2x_2 - x_3$
subject to
$x_1 + x_2 - x_3 \le 3$
$2x_1 + 4x_2 + 3x_3 \le 9$
$x_1, x_2, x_3 \ge 0$
Use the simplex method to solve the problem. Select the correct choice below and, if necessary, fill in the answer boxes to complete your choice.
A. The maximum value of P is when $x_1 =$, $x_2 =$, and $x_3 =$
(Simplify your answers. Type integers or decimals rounded to the nearest tenth as needed.)
B. There is no optimal solution.