$.$ 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 upper and lower control limits involved will receptively be:

$12$ and $8$

$8$ and $12$

$16$ and $4$

$8$ and $28$