[单选题]
In all three types of radioactikru. lq yw;k7t v;4f4lz1o:hvve decay,lsb5 ljrt 5e w+;af19m what value is conserved in addition to electric chalalsfe5 t 9bmj +;wr15rge, energy, and momentum?
A. atomic number
B. neutron number
C. nucleon number
D. none of the given answers
