Which of the following couplings or clutches would be able to prevent the transmission of torsional vibrations from an engine to a reduction gear?

Correct Answer: Option B — Hydraulic fluid-type clutch

Hydraulic fluid-type couplings, or fluid drives, utilize a vortex of oil to transmit power between the impeller and runner. Because there is no direct mechanical connection, the fluid medium acts as a damper, effectively isolating the reduction gear from the engine's torsional vibrations and shock loads.