Among the given series of transition metal ions, one in which all metal ions have 3d2,3p6 electronic configuration is : Option (d), i.e. Ti(Z=22)→Ti2+ (has 20 electrons) V(Z=23)→V3+ (has 20 electrons) Cr(Z=24)→Cr4+ (has 20 electrons) and Mn(Z=25)→Mn5+ (has 20 electrons) Thus, all can show 3d23p6 electronic configuration i.e. option (d) is the correct answer.