What Is the Rate Law for the Following Reaction and Its

What is the rate law for the following reaction and its mechanism?
2 HgCl₂ + C₂O₄^2- → 2 Cl^- + 2 CO₂ + Hg₂Cl₂ (overall reaction)
HgCl₂ + C₂O₄^2- ⇌ HgCl₂C₂O₄^2- (fast)
HgCl₂C₂O₄^2- + C₂O₄^2- → Hg + 2 C₂O₄Cl^2- (slow)
Hg + HgCl₂ → Hg₂Cl₂ (fast)
2 C₂O₄Cl^2- → C₂O₄^2- + 2Cl^- + 2 CO₂ (fast)

A) Rate = k[HgCl₂][C₂O₄^2-]
B) Rate = k[HgCl₂]²[C₂O₄^2-]
C) Rate = k[Hg₂Cl₂]
D) Rate = k[HgCl₂][C₂O₄^2-]²
E) Rate = k[HgCl₂]²[C₂O₄^2-]²