[单选题]
In all three types of radioactive decay, what value is co3 5,xazu ntgnjy:mn 2.nserved itk9 - z;tcmdfhb/00bw n addition to electric chartcmw t -0;/9kbzd 0bhfge, energy, and momentum?
A. atomic number
B. neutron number
C. nucleon number
D. none of the given answers
