D-3

D-3 can refer to the following:
 * World D-3 from Super Mario Bros.: The Lost Levels.
 * Across the Chasm, mission D-3 from Luigi's Mansion: Dark Moon.
 * Level B-7 from Mario vs. Donkey Kong: Tipping Stars, labelled "Level D-3" in the Mario vs. Donkey Kong tech demo.

D-3