Nitric Oxide and Nitrogen Dioxide Are Found in Photochemical Smog

Nitric oxide and nitrogen dioxide are found in photochemical smog. Nitrogen dioxide is formed from nitrogen monoxide in the exhaust of automobile engines. A possible mechanism for this reaction is given below. What is the rate law predicted by the mechanism?
Reaction:
Step 1 (fast) :
Step 2 (slow) :

A) Rate = k[NO]²[O₂]
B) Rate = k[NO]²
C) Rate = k[NO][O₂]
D) Rate = k[NO₂]²
E) Rate = k