For the Reaction 2 N₂O₅ (G) $\rightarrow$ 4 NO₂ (g) + O₂ (G), the Rate Constant, K

For the reaction 2 N₂O₅ (g) $\rightarrow$ 4 NO₂ (g) + O₂ (g) , the rate constant, k = 3.38 × 10^-5 s^-1. What is the overall reaction order?

A) Zero.
B) First.
C) Second.
D) Third.