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 non-zero distance from the wall the person can stand and hear constructive interference? The speed of sound in air is 343 m/s.

Multiple choice:

1.64 m

1.15 m

0.344 m

0.729 m