D# 3/B
The D# 3 chord consists of the D# (Perfect unison) and G (Major third) notes, with B as the bass note.

How to play the D# 3/B chord
- Play B as the lowest bass note in the left hand
- Find D# (Root) on the piano keyboard
- Add G (Major third) — 4 semitones above D#
- Press all 3 notes simultaneously to sound the D# 3/B chord