[单选题]
At the first minima on eiq+ebq( crv,lt1;v9r i ther side of the central zkowq0 *qomcq s85,/ybright spot in a double-slit ek/ 5o, qsq*0cqy8wmzoxperiment, 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
