The correct answer is (c). Lake Titicaca is the highest navigable lake in the world, but it is not the highest lake. The highest lake in the world is Lake Baikal, which is located in Siberia, Russia. Lake Baikal is also the deepest lake in the world, and it is the largest freshwater lake by volume.
Lake Superior is the largest freshwater lake by surface area. It is located in North America, and it is shared by the United States and Canada. Lake Superior is also the third largest lake in the world by surface area, after the Caspian Sea and Lake Victoria.
Tugela Falls is the tallest waterfall in Africa. It is located in KwaZulu-Natal, South Africa. Tugela Falls is a series of five waterfalls that cascade over a cliff face. The total height of Tugela Falls is 948 meters (3,110 feet).