Which of the following ions will exhibit colour in aqueous solution?

La3+ (Z=57) Ti3+ (Z=22) Lu3+ (Z= 71) Sc3+ (Z=21)

Ti3+ (Z=22)

La3+ (Z=57): [Xe] Lu3+ (Z= 71): [Xe]4f14 Sc3+ (Z=21): [Ar] Only Ti3+ (Z=22): [Ar]3d1 ions will exhibit colour in aqueous solution due to d-d transition.