How Many Electrons Are Transferred in the Following Reaction? SO₃^2-(aq) $\rightarrow$

How many electrons are transferred in the following reaction? SO₃^2-(aq) + MnO₄^-(aq) $\rightarrow$ SO₄^2-(aq) + Mn²⁺(aq)

A) 4
B) 10
C) 3
D) 2
E) 6