Which of the following could cause compressor stall?

Correct Answer: Option C — The angle at which the air strikes the compressor rotor blades is too high.

Compressor stall occurs when the angle of attack on the compressor blades becomes excessive, causing airflow separation from the blade surface. This aerodynamic stall disrupts the pressure rise across the stage, leading to a loss of compressor efficiency and potential surge, which can cause severe mechanical damage to the turbine assembly.