E m9/C
The E m9 chord consists of the E (Perfect unison), G (Minor third), B (Perfect fifth), D (Minor seventh) and F# (Major ninth) notes, with C as the bass note.

How to play the E m9/C chord
- Play C as the lowest bass note in the left hand
- Find E (Root) on the piano keyboard
- Add G (Minor third) — 3 semitones above E
- Add B (Perfect fifth) — 7 semitones above E
- Add D (Minor seventh) — 10 semitones above E
- Add F# (Major ninth) — 14 semitones above E
- Press all 6 notes simultaneously to sound the E m9/C chord