Synchronous motors have construction that is identical to:

Synchronous motors are designed with construction elements that are quite similar to alternators, which are also referred to as synchronous generators. Both synchronous motors and alternators operate on the principle of electromagnetic induction and require a magnetic field that rotates at the same speed as the alternating current (AC) frequency.

In both devices, the rotor can be a permanent magnet or an electromagnet, enabling them to achieve synchronism with the rotating magnetic field created by alternating currents in the stator windings. This synchronous operation distinguishes them from other types of motors and generators.

The construction similarities include components such as rotors and stators that are designed to interact with alternating magnetic fields, and a winding setup that allows for effective generation or consumption of electrical energy via synchronous action. This makes option A the most relevant comparison for synchronous motors.

In contrast, AC induction motors rely on differences in rotor speed and stator magnetic fields to operate, while DC shunt and DC series motors are fundamentally different in their operation and construction as they use direct current (DC) instead of alternating current.