As we used Excel Solver to optimize the monthly production of a pharmaceutical company, as part of our in$-$class activity, the "changing cell" is a crucial component. Specifically, what role does the "changing cell" play in this optimization model, and how does it influence the solution?

A$.$ The changing cell tracks the total production costs, allowing Solver to minimize these costs by adjusting production levels while keeping output constant.

B$.$ It represents the targeted profit figures, which Solver adjusts in response to fluctuations in market demand and cost of resources.

C$.$ The changing cell contains the adjustable quantities of each drug that the company intends to produce, directly influencing the maximization of profit by modifying these quantities within the constraints of labor and material availability.

D$.$ It indicates the fixed amount of raw materials in stock, which Solver manipulates to determine the most efficient distribution across various product lines.

E$.$ The changing cell integrates external market dynamics such as competitor activities and economic conditions, which Solver analyzes to refine the company's strategic production decisions.