What are the only two shapes associated with the lateral navigational system?

The correct answer highlights the significance of the shapes used in the lateral navigational system, which employs specific geometric forms to convey essential information to mariners about the safe passage in navigable waters. The lateral system primarily relies on buoys that mark the sides of navigable channels, and the two commonly associated shapes are square and triangle.

In this system, a square shape is typically used to indicate a safe harbor or a point of interest, whereas a triangular shape is utilized to signal the presence of danger or that mariners should exercise caution. Understanding these shapes is crucial for the effective navigation of vessels through channels where proper delineation is necessary for safety and compliance with navigational rules.

The other options do not pertain to the standard markers within the lateral navigational system, as they either consist of shapes that are not employed in this context or do not relate to maritime navigation practices. Knowing this distinction reinforces the importance of recognizing navigational aids correctly for safe maritime operations.