The level of management that is responsible for developing tactical and operational plans and makes up the largest group of managers in most organizations is

Middle Management

Explanation: The Middle management in an organization acts as the intermediary between top level management and the lower level management, They are subordinate to the top level management and superior to the lower level management. They develop tactical and operational plans in conformance with company policies made my top level management. They act as mentor and supervisors to low level management and ensure better productivity. Middle management may include general managers, branch managers and department managers in a company, making up the largest number of managers in most organizations.