Nitrogen Dioxide Decomposes to Nitric Oxide and Oxygen Via the Reaction

Nitrogen dioxide decomposes to nitric oxide and oxygen via the reaction: 2NO₂ → 2NO + O₂
In a particular experiment at 300 °C, [NO₂] drops from 0.0143 to 0.00701 M in 261 s. The rate of disappearance of NO₂ for this period is ________ M/s.

A) 2.79 × 10^-5
B) -8.16 × 10^-5
C) 5.59 × 10^-5
D) 1.40 × 10^-5
E) 35,800