[单选题]
When a gamma ray is emitted from mmwbvh .+j2i7 an unjdt,b z1 s5;yestable nucleus,
A. the number of neutrons and the number of protons drop by two.
B. the number of neutrons drops by one and the number of protons increases by one.
C. there is no change in either the number of neutrons or the number of protons.
D. none of the given answers
