A local manufacturer makes its dog treats using two different flavors: Premium (P) \& Regular (R). Each Premium treat (P) costs $57 a bag to produce \& each Regular treat (R) costs $12 a bag to produce. The company's goal is to minimize its costs. To create the dog treats, each of the 2 flavor products must contain a certain number of units of Fiber, Meat, and Vitamins (as shown in the table below) and they must contain at least 900 units of Fiber, at most 2400 units of Meat, and no more than 1400 units of Vitamins in order for the blend to be effective. Based on the information given above, what is the minimum cost of the blend if the company produces at the optimal amount? \begin{tabular}{l} $5700 \\ $4950 \\ $5900 \\ \hline$5280 \\ \hline$4780 \end{tabular}