A process uses statistical process control. The mean of all sample means is $45$ units. The mean of all sample ranges is $2\mathrm{.}2$ units. There were $10$ samples taken each with $4$ observations. Calculate the lower control limit for the x$-$bar chart.

Question $49$Select one:

a$.$

$44\mathrm{.}318$ units

b$.$

$43\mathrm{.}394$ units

c$.$

None of these answers is even close

d$.$

$0\mathrm{.}000$ units

e$.$

$45\mathrm{.}000$ units