The primary function of an axial compressor rotor blade is which of the following?

Correct Answer: Option B — To impart acceleration to the air mass, resulting in an increase in velocity.

Rotor blades perform work on the air by accelerating it, thereby increasing its kinetic energy. This velocity increase is subsequently converted into pressure energy as the air passes through the following stator vanes, which act as diffusers. This process is fundamental to the compression stage of the Brayton cycle.