Which of the following options does not represent ground state electronic configuration of an atom?

Options

A. `1s^(2) 2s^(2) 2p^(6) 3p^(6) 3d^(8) 4s^(2)`
B. `1s^(2) 2s^(1) 2p^(6) 3s^(2) 3p^(6) 3d^(9) 4s^(2)`
C. `1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(10) 4s^(2)`
D. `1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(5) 4s^(2)`

Answer

B