In gases which waves cannot propagate?

In order to solve this dilemma, one might apply the concept that there should be a force that causes motion in gases that is perpendicular to the wave's path of passage.

Gases cannot propagate transverse waves because there are no forces that can generate motion in the wave's opposite direction. Because every atom in a solid has an "equilibrium site" where the forces exerted on it by all of its nearby atoms are equal, transverse waves can go through solids. One atom will often be drawn back to its equilibrium place if a disturbance pulls it away from it. However, as it moves away from its equilibrium site, it also causes its neighbors to move away from their equilibrium places, and so on. As a result, a transverse wave disturbance spreads throughout the substance.

Hence, the correct answer is option C.