Which component is responsible for transferring power from the engine to a manual transmission?

The clutch disc is the correct answer as it plays a critical role in transferring power from the engine to a manual transmission. When the driver engages the clutch by pressing the pedal, the clutch disc separates from the flywheel, allowing the gear shift lever to change gears without stalling the engine. When the pedal is released, the clutch disc engages with the flywheel again, facilitating power transmission to the transmission and ultimately to the wheels of the vehicle. This process enables smooth gear changes and effective power transfer, which are essential for the operation of a manual transmission.

The flywheel, while important for providing a stable surface for the clutch disc to engage against and aiding in the engine's rotational speed, doesn't directly transfer power itself. The gear shift lever is involved in selecting the gear but does not engage the engine and transmission. The transmission case houses the components but is not part of the power transfer mechanism.