IMAT 2015 Q44 [Electron Configuration]

The atomic number of aluminium is 13. Which electron configuration given below corresponds to the Al^{2+} ion in its ground state?

A. 1s^22s^22p^63s^23p^1
B. 1s^22s^22p^63s^23p^3
C. 1s^22s^22p^6
D. 1s^22s^22p^63s^1
E. 1s^22s^22p^53s^2