In which area was it noted that the depth variations could be dangerous to navigation?

The correct choice highlights that the northeast end of Lake Ontario presents depth variations that can pose dangers to navigation. This area is known for having shallower spots intermixed with deeper regions, which can create challenges for vessels, especially smaller ones or those unfamiliar with the area’s navigation. Navigational hazards could include sudden shifts in water depth that may not be well marked on charts, increasing the risk of grounding or collision. This information is critical for boaters to account for when planning their routes, as it emphasizes the need for careful attention to navigational aids and depth soundings when operating in this section of the lake.

The other areas, while they may have their own navigational challenges, do not have the same level of documented depth variations impacting safety as the northeast end does. This focus on the northeast end is based on historical navigation reports and safety evaluations that highlight specific concerns tied to its unique topography.