For each simplex tableau, decide if it requires additional pivoting, indicates that there is no solution, or is a final tablueau (and the linear programming problem has a solution).

$$\displaystyle\left[\begin{array}{rrrrr|r} P&x_1&x_2&s_1&s_2&\scriptscriptstyle\text{RHS}\cr0 &0 &-18 &17/5 &1 &26 \cr 0 &1 &0 &11/4 &0 &63 \cr \hline 1 &0 &13 &12 &0 &70 \cr \end{array}\right]$$

A. Additional pivoting is required.
B. This is a final tableau; the probem has a solution.
C. This tableau shows that the problem has no solution.

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$$\displaystyle\left[\begin{array}{rrrrr|r} P&x_1&x_2&s_1&s_2&\scriptscriptstyle\text{RHS}\cr0 &0 &-5 &1 &0 &32 \cr 0 &-5 &16 &0 &1 &77 \cr \hline 1 &12 &-6 &0 &0 &0 \cr \end{array}\right]$$

A. Additional pivoting is required.
B. This is a final tableau; the probem has a solution.
C. This tableau shows that the problem has no solution.

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$$\displaystyle\left[\begin{array}{rrrrr|r} P&x_1&x_2&s_1&s_2&\scriptscriptstyle\text{RHS}\cr0 &0 &1 &-15 &0 &27 \cr 0 &13 &0 &-9 &1 &62 \cr \hline 1 &16 &0 &-12 &0 &65 \cr \end{array}\right]$$

A. Additional pivoting is required.
B. This is a final tableau; the probem has a solution.
C. This tableau shows that the problem has no solution.

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$$\displaystyle\left[\begin{array}{rrrrrrr|r} P&x_1&x_2&x_3&s_1&s_2&s_3&\scriptscriptstyle\text{RHS}\cr0 &0 &-16 &0 &18 &0 &1 &44 \cr 0 &1 &0 &5 &-4 &0 &0 &33 \cr 0 &0 &-5 &7 &14 &1 &0 &79 \cr \hline 1 &0 &12 &-18 &-6 &0 &0 &38 \cr \end{array}\right]$$

A. Additional pivoting is required.
B. This is a final tableau; the probem has a solution.
C. This tableau shows that the problem has no solution.