What Is Undergoing Reduction in the Redox Reaction Represented by the Following

What is undergoing reduction in the redox reaction represented by the following cell notation?
$\quad$$\quad$$\quad$ Fe(s) | Fe³⁺(aq) $\|$ Cl₂(g) | Cl^- (aq) | Pt(s)

A) Fe(s)
B) Fe³⁺(aq)
C) Cl₂(g)
D) Cl^- (aq)
E) Pt(s)