If K C for N₂O₄ (G) 2 NO₂ Is

If K c for N₂O₄ (g) 2 NO₂ is 4.5*10^{- 3} at 25 C, what is the value of K c at 25 C for:
2 NO₂ (g) N₂O₄ (g)

A) 2.2×10 ^{- 2}
B) 9.0×10 ^{- 3}
C) 2.2×10²
D) 4.5×10 ^{- 3}
E) 4.5×10³