Answer the following question given this paragraph: 

The figure above also shows how the size of waves is measured ( Figure above ). The highest point of a wave is the crest . The lowest point is the trough . The vertical distance between a crest and a trough is the wave height . Wave height is also called amplitude . The horizontal distance between two crests is the wavelength . Both amplitude and wavelength are measures of wave size.


Q: To figure out the height of a wave you measure the distance between the crest and what?

 Choices:

- drift

- core

- crater

- trough

A:
trough
