Consider a Voltaic Cell That Operates from the Following Redox

Consider a voltaic cell that operates from the following redox reaction:
Al (s) + Cr³⁺ (aq) →Al³⁺ (aq) + Cr (s) What half-reaction operates at the positive electrode of this cell?

A) Al (s) → Al³⁺ (aq) + 3 e ^-
B) Al³⁺ (aq) + 3 e ^- → Al (s)
C) Cr (s) → Cr³⁺ (aq) + 3 e ^-
D) Cr³⁺ (aq) + 3 e ^- → Cr (s)
E) Al³⁺ (aq) + 3 e ^- → Cr (s)