A manager wants to build $3-$sigma control limits for a process. The target value for the mean of the process is $10$ units, and the standard deviation of the process is $6.$ If samples of size $9$ are to be taken, the UCL and LCL will be

a$.$

$-8$ and $28$

b$.$

$16$ and $4$

c$.$

$12$ and $8$

d$.$

$4$ and $16$

e$.$

$8$ and $12$