Who among the following is primarily involved in managing the operations of a firm?

First-line managers are primarily responsible for managing the day-to-day operations of a firm. They operate at the most basic level of management and directly oversee employees who are engaged in production or service delivery. Their focus is on ensuring that operations run smoothly, that teams meet their performance goals, and that day-to-day tasks are executed effectively. They are involved in direct supervision, coaching, and providing feedback to their teams.

In contrast, middle managers typically bridge the gap between first-line managers and top executives. They are more focused on coordinating activities and implementing the strategies developed by higher management rather than directly managing operations. Executive and senior managers are usually involved in strategic planning and decision-making rather than the operational execution that first-line managers handle. Thus, the main role of first-line managers is critical in maintaining the efficiency and effectiveness of the firm's operations.