A# m7/C
The A# m7 chord consists of the A# (Perfect unison), C# (Minor third), F (Perfect fifth) and G# (Minor seventh) notes, with C as the bass note.

How to play the A# m7/C chord
- Play C as the lowest bass note in the left hand
- Find A# (Root) on the piano keyboard
- Add C# (Minor third) — 3 semitones above A#
- Add F (Perfect fifth) — 7 semitones above A#
- Add G# (Minor seventh) — 10 semitones above A#
- Press all 5 notes simultaneously to sound the A# m7/C chord