Nine slots (1-9) are filled with letters A-I. A is in slot 1. I is in slot 9. B is adjacent to C. D is in an even slot. E is in slot 5. F is not adjacent to G. H is in a slot numbered lower than D. How many possible slots can D occupy?

Explanation

A=1, E=5, I=9. D is even: 2,4,6,8. H < D (in slot number). D=2 → H must be in slot 1 (but A=1) → only works if H isn't needed below D among remaining. H could be slot... with D=2, H<2 means H=1 which is A. So D≠2 if H needs a separate slot. D=4,6,8 all allow H to have lower numbered slots. So D has 3 options: 4,6,8.