There is a letter D above my MPH ON MY 2017 HONDA CRV. Never noticed it before and I can't find anything about it in the manual
According to page 11 and 12 of the owner manual, there are two available gauge configurations.
The one you described has the Shift Lever Position Indicator above the speedometer.
There is another gauge cluster style, but it has the Shift Lever Position Indicator to the left of the speedometer.