Question

Will give a medal!!
The graph of the sine curve below is of electromagnetic energy that represents red light:
sine graph with points at 0, 0 and 160, 1 and 320, 0 and 480, negative 1 and 640, 0
What function accurately represents the sine curve for red light?
f(x) = sin pi over 640x
f(x) = sin 640πx
f(x) = sin 320πx
f(x) = sin pi over 320x