Two identical nuclei `A` and `B` of the same radioactive element undergo `beta^(-)` decay. `A` emits a `beta^(-)` particle and changes to `A'`. `B` emits a `beta^(-)` particle and then a `gamma`-photon immediately afterwards, and changes to `B`.

Options

A. A' and b have the same atomic and mass number.
B. A' and b' have the same atomic munber but different mass munbers
C. A ' and B' have different atomic number but the same mass number.
D. A' and B' ae isotopes.

Answer

a