The Superposition of Two Waves

Multiple Choice

The superposition of two waves
And
At the location x = 0 in space results in

A) beats at a beat frequency of 3 Hz.
B) a pure tone at a frequency of 153 Hz.
C) a pure tone at a frequency of 156 Hz.
D) beats at a beat frequency of 6 Hz in a 153 Hz tone.
E) a tone at a frequency of 156 Hz,as well as beats at a beat frequency of 6 Hz in a 153 Hz tone.