What role does a Marine Division primarily undertake?

A Marine Division primarily undertakes the role of seizing and defending advanced naval bases, which is essential to establishing forward operating bases from which critical operations can be conducted. This role capitalizes on the Marine Corps' primary mission of rapid deployment and ability to project power from the sea, allowing for the establishment of a foothold in enemy territory.

By seizing advanced naval bases, the Marine Division ensures that the naval forces have secure locations to support further operations, such as sustaining logistics, conducting training, and enabling follow-on forces to land. This mission often involves amphibious operations, which are a critical aspect of Marine Corps capabilities, emphasizing their unique ability to launch assaults from the sea and establish a presence on land quickly and efficiently.

The other options, while relevant to various military functions, do not encapsulate the primary mission of a Marine Division as effectively. Cyber operations and coordination of humanitarian aid, while important, are typically not the main focus of ground units like a Marine Division.