At 700 K, the Rate Constant for the Following Reaction

At 700 K, the rate constant for the following reaction is 6.2  10^-4 min^-1. How many minutes are required for 20% of a sample of cyclopropane to isomerize to propene?

A) 1,120 min
B) 360 min
C) 3710 min
D) 1.4  10^-4 min
E) 280 min