A Periodic Transverse Wave Is Established on a String Such

Multiple Choice

A periodic transverse wave is established on a string such that there are exactly two cycles traveling along a 3.0-m section of the string. The crests move at 20.0 m/s.
-What is the shortest horizontal distance from a crest to a point of zero acceleration?

A) 0.38 m
B) 0.75 m
C) 1.5 m
D) 3.0 m
E) 6.0 m