Which of the Following Is a Rate Law for a Reaction

Which of the following is a rate law for a reaction that is first order with respect to oxygen?

A) rate = k [NO₂]
B) rate = k [NO₂]² [O₂}^1/2
C) rate = k [NO₂] [O₂}^1/2
D) rate = k [NO₂] [O₂}^1/2 [N₂]^1/2
E) rate = k [NO₂]² [O₂}