The Reaction, 2A₂X₄(g) $\rarr$ 2A₂X₃(g)+ X₂(g), Was Found to Be First Order

The reaction, 2A₂X₄(g) $\rarr$ 2A₂X₃(g) + X₂(g) , was found to be first order. The rate law, therefore, should be:

A) rate = k([A₂X₃]²[X₂]) /[A₂X₄]²
B) rate = k[A₂X₄]²
C) rate = k([A₂X₃][X₂]) /[A₂X₄]
D) rate = k[A₂X₄]
E) rate = k[A₂X₄]²/([A₂X₃]²[X₂])