Is a wave that travels slower than 50 m/s most likely to be a sound wave a light wave or a water wave?

A wave is a transmission of a disturbance in a certain direction from the source.
Water waves are mechanical waves whose media of transmission is water, they have a speed depending on whether the region is shallow or deep. Sound waves are mechanical waves which are longitudinal in nature (with rarefactions and compressions), they travel with approximately 343 m/s in air. Light waves are electromagnetic waves that require no medium for transmission, in vacuum they travel with a speed of 3.0 ×10∧8 m/s. Therefore, the correct answer is water waves.

Why the rest of the question?