Final answer:
The correct answer to the student's question is 'controlling', which is one of the four primary functions of management alongside planning, organizing, and leading.
Step-by-step explanation:
One of the four primary functions of management is controlling. The other three functions are planning, organizing, and leading. Controlling involves monitoring the performance of the organization, identifying any deviations from the plan, and making adjustments to operations as necessary. This function is critical for ensuring that the company's goals and objectives are met. Marketing, financing, and designing are important aspects of business operations, but they are not considered one of the four primary functions of management.