Final answer:
Approximately 1 million Canadian citizens served in the military during the Second World War, reflecting Canada's significant contribution to the global conflict.
Step-by-step explanation:
During the Second World War, roughly 1 million Canadian citizens served in the military. This was a significant contribution considering the size of the country at the time and reflected the global nature of the war, which required extensive manpower from all participant nations. The armed forces of the warring nations numbered about 30 million, and the total number of military and civilian casualties was probably between 35 and 40 million. Canadian involvement in WWII was considerable, with many women taking on new roles at home and overseas to support the war effort.
The vast scale of the conflict affected every aspect of life in involved countries, including population displacement and reshaping economies and societies. While the options a) Around 500,000, b) Around 1 million, c) Around 2 million, and d) Around 5 million are presented, the correct answer to the number of Canadian citizens who served during World War II is b) Around 1 million.