[单选题]
If an atom's atomic 6 2/x/sa x; rrzd5qdykw3yot6na3 1jt,g kuu08omm6u h.e 7udxumber is given by Z, its atomic mass by A, and its neutron number by N, whi3t1h8 x mu uaeg7.0d kjuo,6much of the following is correct?
A. N = A + Z
B. N = Z - A
C. N = A - Z
D. none of the given answers