Final answer:
The bass note of a second inversion E-flat minor triad is B♭, which is the fifth of the triad.
Step-by-step explanation:
In a second inversion E-flat minor triad, the bass note is the fifth note of the triad. An E-flat minor triad is made up of the notes E♭ (root), G♭ (minor third), and B♭ (fifth). When this triad is in second inversion, the fifth of the triad, which is B♭, becomes the bass note.