An objective function \(Z\) of primal variables (\(x_1\) and \(x_2\)) is described below:
\[ \begin{gathered} \text{Minimize } Z = 0.07x_1 + 0.05x_2 \\ \text{subject to} \\ 0.1x_1 \ge 0.4 \\ 0.1x_2 \ge 0.6 \\ 0.1x_1 + 0.2x_2 \ge 2.0 \\ 0.2x_1 + 0.1x_2 \ge 1.8 \\ x_1, x_2 \ge 0 \end{gathered} \]
\(W\) is the objective function of the dual of \(Z\). \(k_1\), \(k_2\), \(k_3\), and \(k_4\) represent the corresponding dual variables. Which one of the following options represents the correct form of \(W\)?