Till tip of south america
New France, French Nouvelle-France, (1534–1763), the French colonies of continental North America, initially embracing the shores of the St. Lawrence River, Newfoundland, and Acadia (Nova Scotia) but gradually expanding to include much of the Great Lakes region and parts of the trans-Appalachian West.
The key waterways in the south during the civil war were: Mississippi,Ohio and Tennessee rivers
Both side aware that controlling these rivers would cut down oppositions food and weaponry supplies along with limiting the opposition's ability to mobilize. The union army managed to leverage on this situation better than the Confederates, leading to the union's victory during the civil war.
Definitely B.) Alaska I hope this Helps