Select the correct configuration(s) of the given species If Aufbau rule is not followed

M2+ (electrons =24,Z=26 )  Thus, EC of M=[ Ar ]4s23d6In the formation of M2+, electrons are taken out from valence shell (4s). Thus, M2+ has EC is [Ar] 3d6 : Incorrect(2) M (electrons = 24, Z = 24)This represents Cr.Thus [Ar] 3d54s1 : Correct(3) M+(electrons =24,Z=25)M:[ Ar ]4s23d5M+=[Ar ]4s13d5: Correct (4) If Aufbau rule is not followed, electrons are filled in available.