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. Because there is no mechanical connection between the input and output members, they effectively dampen torsional vibrations and shock loads, protecting reduction gears from the cyclic torque fluctuations inherent in reciprocating internal combustion engines.