Answer:
Attach the image,
I'll edit this post and answer your question.
im srry but huh wut do u mean
D is the correct answer.
In the badly drawn diagram attached, you will find the <em>yellow</em> represents wavelength, which is the distance between identical points on consecutive waves.
The <em>green</em> represents the amplitude, which is the distance between the origin (middle) and crest/trough (top/bottom)