What Is the Empirical Formula of the Only Product of the Following

Multiple Choice

What is the empirical formula of the only product of the following reaction

__ N₂O₃(g) + __ O₃(g) $\rightarrow$
If 3.00 L of N₂O₃ react completely with 1.00 L of O₃ to give 6.00 L of the product, all gases measured at STP?

A) NO
B) NO₂
C) NO₃
D) N₂O₅
E) none of the above