X, Y and Z are chemical elements. X and Y are located in the same period of the Periodic Table. Y and Z are located in the same group of the Periodic Table. What could be the electronic configurations of X, Y and Z?
- AX: $2,4$; Y: $2,7$; Z: $2,8,4$
- BX: $2,4$; Y: $2,7$; Z: $2,8,7$
- CX: $2,4$; Y: $2,8,4$; Z: $2,8,7$
- DX: $2,8,4$; Y: $2,8,7$; Z: $2,4$