Mechanical waves are classified according to
a. their size.
b. their shape.
c. how they move.
d. their source.

Mechanical waves are classified according to how they move, that is letter C. Mechanical Waves are waves made through medium such as tube. There are two types of mechanical waves, they are longitudinal and transverse. Longitudinal or compressional waves are when the particles in the tube do not move in accordance of the wave, just back and forth with respect to their equilibrium positions. The displacement of the wave particles is parallel to the wave made. Transverse waves are when the particles moving against the oscillating up and down about with respect to their equilibrium positions. Therefore the displacement of the wave particles is perpendicular to the wave made