Consider a production process that produces tires. A quality engineer has taken $15$ samples, each containing $200$ tires. The total number of defective tires over the $15$ samples is $340.$ The centerline for the control chart is

a$.0\mathrm{.}08$

b$.0\mathrm{.}11$

c$.0\mathrm{.}16$

d$.0\mathrm{.}21$