Which lake is known for draining into the St. Lawrence River?

Lake Ontario is the correct choice because it is located at the eastern end of the Great Lakes system and is the last lake in the chain before the water flows into the St. Lawrence River. The St. Lawrence River serves as the outlet for Lake Ontario, and this river ultimately leads to the Atlantic Ocean. This hydrological connection is significant for both environmental and economic reasons, as it facilitates transportation and trade.

The other lakes, while they are part of the Great Lakes system, do not drain into the St. Lawrence River. Lake Superior has its own outflow into the St. Marys River, while Lake Erie drains into Lake Ontario through the Niagara River. Lake Michigan, situated entirely within the United States, does not connect to the St. Lawrence River at all, as it flows into Lake Huron via the Straits of Mackinac. Thus, Lake Ontario's position and its linkage to the St. Lawrence River make it the correct answer for this question.