Final answer:
The largest city in Upper Canada is Toronto, which makes 'A. Toronto' the correct answer. The base for British operations during the majority of the American Revolutionary War was New York.
Step-by-step explanation:
The largest city in Upper Canada is Toronto. Hence, the correct answer to the question 'What's the largest city in Upper Canada?' is 'A. Toronto'. It is important to clarify that the term 'Upper Canada' refers to a historical region and former British colony that is now part of the Canadian province of Ontario. Kingston, Hamilton, and London are cities in Ontario, but they are not larger than Toronto. Furthermore, the city that served as the base for British operations for most of the American Revolutionary War was New York, making the correct answer to that additional question 'B. New York'.