[单选题]
At the first maxima on eitm/j+xeyp vz ,n:mtz/7her side of the centsp3/bzmf - mo2tk+ f3oz9 )fzjral bright spot in a double-slit expe jzk9zbz-+offmf op2tm)3 s3/riment, light from each opening arrives
A. in phase.
B. $90^{\circ}$ out of phase.
C. $180^{\circ}$ out of phase.
D. none of the given answers
