OK
browningdmis i stand corrected. I assumed since the leader lines were inward then it would refer to the ID. But one of the 16 fundamental rules of dimensioning (rule g) states "Dimensions should be arranged for optimum readability. Dimensions should be shown in true profile views and refer to visible outlines."
So with that being said since the ID is not visible in this view then it cannot be referred to as Datum A.
