Final answer:
The correct option is a) Main shaft. The shaft also known as the output shaft in a mechanical system like a car's transmission is the main shaft, which transfers the engine's power to the rest of the mechanism.
Step-by-step explanation:
The shaft that is also called the output shaft is (a) Main shaft. The output shaft is the component in a mechanical system that carries the torque from the engine or motor to the rest of the system, ultimately resulting in the movement of the vehicle or machinery. For example, in a manual transmission system in a car, the main shaft is the output shaft that transmits the power from the engine to the drive wheels.
The correct answer is d) Countershaft. In mechanical systems such as engines and transmissions, the countershaft is also known as the output shaft. It is responsible for transferring power from the engine or transmission to the wheels or other driven components. For example, in a manual transmission, the countershaft receives power from the input shaft and transmits it to the gears and ultimately the wheels.