Final answer:
The clutch friction disc is the component that is splined to the transmission's input shaft, facilitating the transmission of engine power to the gears.
Step-by-step explanation:
The correct answer is option a) clutch friction disc. In a vehicle's transmission system, the clutch friction disc is the component that is splined to the input shaft of the transmission. This disc interlocks with the splines, allowing it to rotate with the input shaft while still being able to slide along it as the clutch is engaged and disengaged. The friction material on the clutch disc engages with the flywheel, which is bolted to the engine crankshaft, to transmit the engine's power to the transmission. The other components listed, including the release bearing, flywheel, and pressure plate, play critical roles in the operation of the clutch system, but they do not spline directly to the transmission's input shaft.
The correct answer is option d) pressure plate. The pressure plate in a clutch system is the component that is splined to the input shaft of the transmission. The pressure plate applies pressure to the clutch friction disc, which in turn connects the engine to the transmission.