Nitric Oxide and Nitrogen Dioxide Are Found in Photochemical Smog $\rightarrow$

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: 2NO(g) + O₂(g) $\rightarrow$ 2NO₂(g)
Step 1 (fast) : NO + NO $\rightarrow$ N₂O₂
Step 2 (slow) : N₂O₂ + O₂ $\rightarrow$ 2NO₂

A) Rate = k[NO]²[O₂]
B) Rate = k[NO]²
C) Rate = k[NO][O₂]
D) Rate = k[NO₂]²
E) Rate = $k \frac { \left[ \mathrm { NO } _ { 2 } \right] ^ { 2 } } { [ \mathrm { NO } ] ^ { 2 } \left[ \mathrm { O } _ { 2 } \right] }$