The average mean is $250\mathrm{.}645$ and the average standard deviation is $0\mathrm{.}035.$ For sample size $10,$ the control limits for the S$-$chart are

Select one:

a$.$ LCL$=0\mathrm{.}009,$ UCL $=0\mathrm{.}060$

b$.$ LCL$250\mathrm{.}611,$ UCL $=250\mathrm{.}679$

C$.$ LCL$251\mathrm{.}392,$ UCL $=251\mathrm{.}411$

Od$.$ LCL $=250\mathrm{.}738,$ UCL $=251\mathrm{.}854$