Two Guitar Players Are Simultaneously Playing a Note

Multiple Choice

Two guitar players are simultaneously playing a note. One note is played at 420 Hz; the other is played at 424 Hz. The resulting tone will be at

A) 844 Hz with a beat frequency at 4 Hz.
B) 422 Hz with a beat frequency at 2 Hz.
C) 422 Hz with a beat frequency at 4 Hz.
D) 2 Hz with a beat frequency at 422 Hz.
E) 4 Hz with a beat frequency at 422 Hz.