An Observer Stands 3 M from Speaker a and 4

Multiple Choice

An observer stands 3 m from speaker A and 4 m from speaker B.Both speakers,oscillating in phase,produce 170 Hz waves.The speed of sound in air is 340 m/s.What is the phase difference (in radians) between the waves from A and B at the observer's location,point P?

A) 0
B)
C) π
D) 2π
E) 4π