Which statement best defines why sound waves are mechanical waves?

a. they require a medium in which to travel
b. they can travel through a vaccum
c. they can travel only through solids
d. they can travel through gases

The correct answer among the choices presented above is option A. Sound waves are considered as mechanical waves because they require a medium in which they can travel through. A mechanical wave is a wave that cannot transmit energy in a vacuum. It needs something to move energy.

The correct answer is antinodes