are associated

$5.$ The isomerization of cyclopropane to propylene is a first$-$order process with a half$-$life of $10$ minutes at $500C.$ The time it takes for the partial pressure of cyclopropane to decrease from $1\mathrm{.}0$atm to $0\mathrm{.}125$atm at $500C$ is closest to

A$)30$ minutes

B$)80$ minutes

C$)87\mathrm{.}5$ minutes

D$)1000$ minutes