How should a team mark a T intersection?

The correct method for marking a T intersection in a cave or cavern diving scenario involves placing a cookie next to the intersection. A cookie, in this context, is a physical marker that is typically a weighted object or a distinct item that can be easily identified. The use of a cookie allows divers to quickly identify the intersection point and distinguish between the diver's exit line and the continuation of the main guideline.

Using a cookie is effective because it provides a clear visual reference at a point where there might be multiple potential paths for diving and aids in navigation, ensuring team members can easily find their way during a potentially confusing situation. Marking with a cookie helps maintain orientation and ensures safety by assisting divers in recognizing where to turn or continue as they navigate through the cavern system.

The other options may not provide the same level of clarity or effectiveness for marking a T intersection.