Which of the following is NOT a method of reconnaissance mentioned?

The correct choice indicates that "Sea" is not a recognized method of reconnaissance in the context of this training. Reconnaissance methods are typically classified into categories that primarily include ground, air, and map reconnaissance.

Ground reconnaissance involves physical observation and data collection on the terrain and enemy positions through techniques such as patrols and foot or vehicular surveys. Air reconnaissance utilizes aerial platforms, such as drones or aircraft, to gather intelligence from above, providing a broader view of the landscape and enemy movements compared to ground methods.

Map reconnaissance, though not a physical method, is essential for analyzing geographical data, terrain features, and the layout of potential areas of interest. Collectively, these methods are pivotal for military planning and operational readiness.

"Sea" reconnaissance, while a component of maritime operations, is not typically categorized similarly to the traditional land and aerial methods outlined in a course focused on gunnery practices. Thus, identifying "Sea" demonstrates an understanding of the specific reconnaissance techniques pertinent to the course material.