$2.[10$pts total$]$ A production area has $4$ processing stations. Although the stations are currently lined up as shown in the following diagram, the operations are independent of each other, and their order can be changed if desired. Given the arrival and effective coefficients of variation $($CV$)$ and utilizations shown in the diagram.longrightarrow$\{\begin{array}{ccc}\text{:}[& \text{S}\text{t}\text{a}\text{t}\text{i}\text{o}\text{n}A\text{:}& ]\\ C{V}_e=1\mathrm{.}2\\ =0\mathrm{.}75\end{array}$longrightarrowlongrightarrow$\{\begin{array}{ccc}\text{:}[& \text{S}\text{t}\text{a}\text{t}\text{i}\text{o}\text{n}B\text{:}& ]\\ C{V}_e=0\mathrm{.}5\\ =0\mathrm{.}15\end{array}$longrightarrowlongrightarrow$\{\begin{array}{ccc}\text{:}[& \text{S}\text{t}\text{a}\text{t}\text{i}\text{o}\text{n}C\text{:}& ]\\ C{V}_e=0\mathrm{.}08\\ =0\mathrm{.}25\end{array}$longrightarrowlongrightarrow$\{\begin{array}{ccc}\text{:}[& \text{S}\text{t}\text{a}\text{t}\text{i}\text{o}\text{n}D\text{:}& ]\\ C{V}_e=0\mathrm{.}01\\ =0\mathrm{.}85\end{array}$

a$.[5$pts$]$ How would you rearrange the stations to minimize the impact of variability within the line? Explain your reasoning.

b$.[5$pts$]$ Assuming the line was to stay as shown, if you were given the resources to increase capacity or decrease variability at just one station, which would you choose? $($you must choose one$).$ Explain your reasoning.