[单选题]
If an atom's atomic number is g7 g3kq,*yzc oijtc1,pi9gsgm9g* rp 9iven by Z, its atomic mass by A, and ito0)m/y0ztjkpn b g+ )ys neutron number by N, which of n okz t)m0y/by0) pg+jthe following is correct?
A. N = A + Z
B. N = Z - A
C. N = A - Z
D. none of the given answers
