Which of the following is the minimum cost for an assignment problem given below?
$$\text{Jobs} \begin{array}{|l|l|l|l|l|ll|} \hline & & \text{A} & \text{B} & \text{C} & \text{D} \\\hline & \text{I} & \text{5} & \text{3} & \text{2} & \text{8} \\\hline \text{Workers} & \text{II} & \text{7} & \text{9} & \text{2} & \text{6} \\\hline & \text{III} & \text{6} & \text{4} & \text{5} & \text{7} \\\hline & \text{IV} & \text{5} & \text{7} & \text{7} & \text{8} \\\hline \end{array}$$
- $13$
- $16$
- $17$
- $18$