[单选题]
If an atom's atomic 8 :wgyqoszav2t y)*2mw ml.ve(by81z1gtq 6unumber is given by Z, its atomic mass by A, and its neutron numbeb(u1ytlw.6 8mz gqe1v r by N, which of the following is correct?
A. N = A + Z
B. N = Z - A
C. N = A - Z
D. none of the given answers
