Two In-Phase Loudspeakers Are Placed Along a Wall and Are

Multiple Choice

Two in-phase loudspeakers are placed along a wall and are separated by a distance of 4.00 m. They emit sound with a frequency of 514 Hz. A person is standing away from the wall, in front of
One of the loudspeakers. What is the closest nonzero distance from the wall the person can stand
And hear constructive interference? The speed of sound in air is 343 m/s.

A) 1.2 m
B) 1.6 m
C) 0.73 m
D) 0.34 m