Three work study analysts are rating an employee. Work study analyst $1$ rates the employee at PRF $=1\mathrm{.}0$ and an observed time of $3\mathrm{.}0$ minutes per unit. Work study analyst $2$ rates the employee at PRF $=0\mathrm{.}8$ and an observed time of $2\mathrm{.}9$ minutes per unit. Work study analyst $3$ rates the employee at PRF $=1\mathrm{.}1$ and an observed time of $3\mathrm{.}1$ minutes per unit. What should the standard time be$,$ assuming an allowance factor of $15\%?$

Question $8$ options:

$3\mathrm{.}2187$ minutes per unit

$3\mathrm{.}3492$ minutes per unit

$3\mathrm{.}3465$ minutes per unit

$3\mathrm{.}3492$ minutes per unit