Writing alphabets as sequence of natural numbers from 1 to 26 ,

we get :: H==8 ;; E== 5 ;;J==10

we observe that sum in each quadrant of circle will be 16

H+ 8 == 8 +8 == 16 ;;; 6+ J = 6 + 10 ==16 ;;;; 11 + E == 11 + 5 == 16;;

Hence;; ? + 1 == 16 ;;; ? == 15 ;;; ?== O