Pick out th

The wrong electronic configurations are a), c), d).

In a) 1s² 2s² 2p⁷, p subshell can have a maximum of only 6 electrons.

In c) 1s² 2s² 2p⁵ 3s¹, According to Aufbau rule electrons will be filled first in that subshell which has less energy and when less energy subshell will become full filled then after this next subshell will be filled.

In d) 1s² 2s² 2p⁶ 3s² 3p⁶ 3d² 4s¹, here 4s subshell will be full filled first and after this 3d subshell will fill because 4s subshell has less energy than 3d subshell.