The correct answer is option 4: Keil Canal links the North Sea and the Baltic Sea. The Keil Canal, also known as the Kaiser Wilhelm Canal, is an artificial waterway in northern Germany that connects the North Sea with the Baltic Sea. It is located in the state of Schleswig-Holstein and is considered an important shipping route.
Option 1, which states that the Keil Canal links the Pacific and Atlantic Oceans, is incorrect. The Keil Canal is not connected to either of these oceans.
Option 2, which states that the Keil Canal links the Mediterranean Ocean and the Red Sea, is also incorrect. The Mediterranean Ocean does not directly connect to the Red Sea through the Keil Canal.
Option 3, which states that the Keil Canal links the Mediterranean Ocean and the Black Sea, is also incorrect. The Keil Canal does not connect these two bodies of water.
Therefore, the only correct option is option 4, which states that the Keil Canal links the North Sea and the Baltic Sea.