`A` and `B` are isotopes. `B` and `C` are isobars. All three are radioactive. Which one of the following is true.
A. `A,B` and `C` must belong to the same element
B. `A,B` and `C` may belong to the same element
C. It is possible that `A` will change to `B` through a radioactive decay process
D. It is possible that `B` will change to `C` through a radioactive decay process
