[单选题]
At the first maxima on either side of the cen60i*u+v;v o tij 3 q(vi(nloaotral bright spot in a(wn *gi-kqsi k2kky1e4j(3v v double-slit experiment, light from eachkkwk2yk(q4s* jv gi i v-ne31( opening arrives
A. in phase.
B. $90^{\circ}$ out of phase.
C. $180^{\circ}$ out of phase.
D. none of the given answers
