A wave has an amplitude of 0.2 cm. What does this mean?

Select one:

- The horizontal distance between a crest and a trough is 0.2 cm.

- The distance between the resting point and the maximum height of the wave is 0.2 cm.

- The distance between two crests is 0.2 cm.

- The vertical distance between a crest and a trough is 0.2 cm.