What Half-Reaction Occurs at the Cathode During the Electrolysis of Molten

What half-reaction occurs at the cathode during the electrolysis of molten potassium bromide?

A) K(s) → K⁺(l) + e^-
B) Br₂(l) + 2 e^- → 2 Br^-(l)
C) 2 Br^-(l) → Br₂(l) + 2 e^-
D) 2 K⁺(l) + 2 e^- → 2 K(l)
E) 2 H₂O(l) + 2 e^- → H₂(g) + 2 OH^-(l)