The decomposition of dinitrogen tetroxide to nitrogen dioxide at 400°C follows second-order kinetics with a rate constant of 9.35 × 10⁻³ M⁻1 s⁻1. Starting with 1.00 M N₂O₄, how many minutes will it take for 15.5% to be left unreacted?
a) 447 minutes
b) 322 minutes
c) 141 minutes
d) 92 minutes