2 < 3d-4 < 15

Add 4 to all three sides, to get 3d alone in the middle

 2 < 3d-4 < 15
+4     +4   +4
 6 < 3d   < 19

Divide by 3 to get d alone in the middle:

 6/3 < 3d/3 < 19/3
    2 < d < 6 1/3

The only integers that are between 2 and 6 1/3 are these:

    3,4,5 and 6

Edwin