Add a dotted line to your graph to show the maximum population this environment can
theoretically support. this is called the

c is the answer : )               your welcome

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave

i think its both a and b