Final answer:
Mitzie, holding the position of CEO at RST Development Company, is part of the top management tier and is responsible for strategic planning and high-level decision-making.
Step-by-step explanation:
Mitzie, as the chief executive officer of RST Development Company, is in the top management level of the company. The top management is responsible for setting goals, defining the direction of the company, and making decisions that affect the entire organization. This level of management usually consists of positions such as CEO, CFO, and COO, who work on strategic planning and aligning the company's activities with its overall objectives.