Standing Waves Can Be Set Up in a String When

Multiple Choice

Standing waves can be set up in a string when two waves that are

A) of the same frequency and amplitude, but are opposite in direction of travel, meet each other.
B) of the same frequency, amplitude, and direction of travel are also 180° out of phase.
C) of the same frequency, amplitude, and direction of travel meet each other.
D) of the same frequency, amplitude, and velocity meet each other.