Which type of command structure involves one nation exercising control over forces contributed by others?

The correct answer is the Lead Nation Command Structure. This type of command structure occurs when one nation assumes the primary responsibility for the command and control of forces contributed by other nations. In this structure, the lead nation coordinates operations, logistics, and strategic objectives, ensuring that the collective efforts of all contributing nations are aligned and effective.

This arrangement is particularly useful in multinational operations, as it simplifies the command and communication processes, enabling a single point of authority that can make decisions and issue orders on behalf of the collective coalition forces. The lead nation typically has a more extensive military capability and the necessary resources to manage the diverse forces it leads, thus enhancing operational efficiency.

In contrast, options like Integrated Command Structure typically involve forces from different nations operating with a cohesive command where roles and leadership are shared rather than dominated by a single nation. The National Command Structure refers to a country's own internal command organization, while Shared Command Structure suggests a more equitable approach to command that may not delineate a lead nation.