Identify the Lewis Base in the Following Reaction: SO₂ (G) $\rightarrow$

Identify the Lewis base in the following reaction: SO₂ (g) +H₂ O(l) $\rightarrow$ H₂ SO₃ (aq)

A) SO₂
B) H₂O
C) H₂SO₃
D) None of these is a base.
E) All of these are bases.