Assuming all the dropdowns are meant to have the same conditional shading outcomes, the following code is all you'll need.
Code:
Private Sub Document_ContentControlOnExit(ByVal CCtrl As ContentControl, Cancel As Boolean)
Application.ScreenUpdating = False
Dim lClr As Long
With CCtrl
If .Type <> wdContentControlDropdownList Then Exit Sub
With .Range
If .Information(wdWithInTable) = False Then Exit Sub
Select Case .Text
Case "N/R": lClr = wdColorLightTurquoise
Case "Yes": lClr = wdColorPink
Case "No": lClr = wdColorBrightGreen
Case Else: lClr = wdColorAutomatic
End Select
.Cells(1).Range.Shading.BackgroundPatternColor = lClr
End With
End With
Application.ScreenUpdating = True
End Sub