Point out the letter which represents Indians and Historians but not politicians on the basis of these three circles?

To find the intersection representing Indians and Historians but excluding Politicians:
1. Identify the area shared jointly by the 'Indians' circle and the 'Historians' circle.
2. Exclude any portions of this overlap that drop inside the third circle representing 'Politicians'.
3. The distinct single-letter code occupying this exact specific region is 'b'.