Which organization prescribes the shipping routes on Lake Ontario?

The correct answer is the Canadian Coast Guard. This organization plays a crucial role in managing and overseeing shipping routes on Lake Ontario. The Coast Guard is responsible for ensuring the safety of navigation and the efficient movement of vessels within Canadian waters, which includes monitoring shipping patterns, maintaining navigational aids, and enforcing regulations that govern waterway use.

The other organizations mentioned have different roles. The International Maritime Organization focuses on global shipping regulations and safety but does not determine specific shipping routes on individual lakes. Transport Canada deals with broader transportation policy and regulation in Canada, including aspects of maritime transport, but does not directly prescribe the shipping routes. The LCA (Canadian Shipowners Association) represents the interests of Canadian shipowners and may advocate for policies but is not involved in the practical regulation of shipping routes on Lake Ontario.