Given that the sum of the angles of any triangle is 180°, adding the expressions of each angle and setting them equal to 180° will give the value of 'x' and allow you to evaluate the angles.
2x + 5x + 11x = 180
18x = 180
18x/18 = 180/18 or x = 10
m∠A = 2x or 2(10) = 20°
m∠B = 5x or 5(10) = 50°
m∠C = 11x or 11(10) = 110°
Out of the choices given, the only one that is true is that m∠A = 20°.
