Two in$-$phase loudspeakers are placed along a wall and are separated by a distance of $4\mathrm{.}00$ 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. The distance d$1=3$m$.$ Is the interference constructive? The speed of sound in air is $343$ m$/$s$.$

A$)0\mathrm{.}34$ m B$)0\mathrm{.}73$ m C$)1\mathrm{.}2$ m D$)1\mathrm{.}6$ m