A process has an output of $270$ ?defects in $5400$ ?units. Each product goes through $8$ ?steps, with one defect opportunity at each step. What is the short term sigma level of the process?

A $3\mathrm{.}1$

B $5\mathrm{.}3$

C $2\mathrm{.}7$

D $4\mathrm{.}0$

E $4\mathrm{.}9$