A process, when in control, produces a normally distributed output with a mean X$-$bar of $200$ and a mean range of R$-$bar of $20.$ When using samples of size $20$ and $3$ Standard Deviation control limits$,$ then which of the following is the lower control limit of the R chart?

$8\mathrm{.}28$

$10\mathrm{.}42$

$20\mathrm{.}00$

O $4\mathrm{.}84$

$09\mathrm{.}68$