Given the Following Information, HF (Aq) H + (Aq)

Given the following information, HF (aq) H + (aq) + F - (aq) K c = 6.8*10^{- 4} H₂ C₂ O₄ (aq) 2 H + (aq) + C₂ O₄ 2 - (aq) K c = 3.8*10^{- 6} What is the value of the equilibrium constant for the following reaction?
2 HF (aq) + C₂ O₄ 2 - (aq) 2 F - (aq) + H₂ C₂ O₄ (aq) K c = ??

A) - 5.2×10 ^{- 9}
B) 2.6×10 ^{- 9}
C) 9.9×10 ^{- 8}
D) 1.4×10 ^{- 3}
E) 0.12