If the capacitor of a single-phase motor is short-circuited

The correct answer is: A. the motor will not start.

A single-phase motor uses a capacitor to create a rotating magnetic field. When the capacitor is short-circuited, the magnetic field is not created and the motor will not start.

Option B is incorrect because the motor will not start if the capacitor is short-circuited.

Option C is incorrect because the motor will not run in reverse direction if the capacitor is short-circuited.

Option D is incorrect because the motor will not run in the same direction at reduced r.p.m. if the capacitor is short-circuited.