Select Case Target.Column
Case 1
Target.Cells(1).Validation.Add Type:=xlValidateList, Formula1:="=dataA"
Case 2
Target.Cells(1).Validation.Add Type:=xlValidateList, Formula1:="=dataB"
Case 3
Target.Cells(1).Validation.Add Type:=xlValidateList, Formula1:="=dataC"
End Select