How do I find MQR and what does it equal?

Answer:
B
Step-by-step explanation:
The inscribed angle Q is half the measure of its intercepted arc , so
arc RS = 2 × 75° = 150°
The sum of the 3 arcs = 360° , then
arc QR = 360° - (150 + 133)° = 360° - 283° = 77° → B