 Complete the following phrase:  In London, Prime Minister William Pitt named Amherst as his new commander-in-chief of North America for 1759. The Louisbourg victory opened the St. Lawrence River to the British, and Amherst devised a three-pronged attack against French Canada: a push up the St. Lawrence to attack Quebec, another northward invasion from Albany by way of lakes George and Champlain, and pressure against the French in the west at Fort Niagara. The 1759 battle for Quebec City was 