For nuclide `""_(Z)X""^(A)`, which of the following changes snot take place in respective decay:
A. Both (A) and (Z) decreases in `alpha`-decay
B. Both (A) and (Z) do not change in `gamma`-decay
C. (A) does not change but (Z) decreases by one unitun positrondecay or k-electron capture
D. Both (A) and (Z) increases in `beta`-decay
