If in ΔPQR, ∠P = 120°, PS ⊥ QR at S and PQ + QS = SR, then the measure of ∠Q is:

Answer: Option C

Suppose PMQ is isosceles triangle
Since, PQ + QS = SR
Hence MR = a
∠P + ∠Q + ∠R = 180°
120° + 2θ + θ = 180°
θ = 20°
∠Q = 2θ = 40°