[单选题]
At the first minima on either s 3ixqqq -bzn1nc km:fp-6f2 1yide 3f.1f vao+)qad2a reo vj-wo(of the central bright spot in a double-slit experimefro)j wo e1av(f3q.dva +o2a-nt, 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
