Explanation:

Servomotor is a type of motor that is typically used for precise control of position, speed, and acceleration in various applications. The correct answer is option B, which refers to a pair of synchronous transmitter and control transformer. Let's break down the explanation further:

Armature controlled FHP DC motor:
- Armature controlled FHP DC motor is a type of motor where the speed is controlled by varying the armature voltage.
- While this type of motor can be used for certain applications, it is not specifically referred to as a servomotor.

A pair of synchronous transmitter and control transformer:
- A servomotor typically consists of a pair of synchronous transmitter and control transformer.
- The synchronous transmitter generates a signal that represents the desired position, speed, or other parameters.
- The control transformer then receives this signal and adjusts the motor to achieve the desired output.

Tach generator:
- A tach generator is a type of sensor that generates a voltage proportional to the speed of the motor.
- While tach generators can be used in servomechanisms for feedback control, they are not the primary components of a servomotor.

Amplidyne:
- Amplidyne is an electromechanical amplifier that can control large amounts of power with relatively small control signals.
- While amplidynes can be used in control systems, they are not typically associated with servomotors.

In conclusion, a servomotor consists of a pair of synchronous transmitter and control transformer, which work together to provide precise control over position, speed, and acceleration in various applications.