Which of the following squadrons has never operated in the area encompassed by the U.S. Navy's Second Fleet?

The North African Squadron is the correct choice because it was primarily focused on operations involving the coast of North Africa and the Mediterranean Sea. This squadron was tasked with protecting American interests in that region, which generally falls outside the operational area of the U.S. Navy's Second Fleet, whose focus is on the North Atlantic and specific portions of the surrounding areas.

In contrast, the Pacific Squadron operated in the Pacific Ocean and frequently interacted with waters relevant to Second Fleet operations in the broader strategic context, particularly during times of conflict. The North Atlantic Squadron was explicitly formed to operate within the Atlantic, directly aligning it with the Second Fleet's area of responsibility. The Northern European Squadron also had missions that involved operating near or within the North Atlantic region, aligning with the Second Fleet’s objectives. Thus, the activities of these squadrons placed them within or adjacent to the operational scope of the Second Fleet, while the North African Squadron was primarily active well outside of that realm.