Which of the Following Formula Unit or Net Ionic Equations $\rightarrow$

Which of the following formula unit or net ionic equations represents a disproportionation reaction?

A) Fe + 3 Ag⁺ $\rightarrow$ Fe³⁺ + 3 Ag
B) 2 HNO₃ + SO₂ $\rightarrow$ H₂SO₄ + 2 NO₂
C) ClO^- + Cl^- + 2 H⁺ $\rightarrow$ Cl₂ + H₂O
D) CH₄ + 2 O₂ $\rightarrow$ CO₂ + H₂O