[单选题]
In a nuclear reaction, what val 2ive:5haj ;yl ckl c-59i-( (mhyo)tckni 2ksue is conserved in addition to electric charge, energy, and momeik(oc - 5 ic2hklstc(m)9-nykntum?
A. atomic number
B. neutron number
C. nucleon number
D. none of the given answers
