For the feasible region shown below, the non-trivial constraints of the linear programming problem are (A) $x + y \le 5, x + 3y \le 9$ (B) $x + y \le 5, x + 3y \ge 9$ (C) $x + y \ge 5, x + 3y \le 9$ (D) $x + y \ge 5, 3x + y \le 9$