Final answer:
The BNA Act of 1867 was signed by Queen Victoria, formalizing the creation of the Dominion of Canada. Leading Canadian figures played key roles in the process, but it was Queen Victoria's assent that enacted the law.
Step-by-step explanation:
The BNA Act of 1867, also known as the British North America Act, was an important statute passed by the British Parliament that led to the formation of the Dominion of Canada. It unified the colonies of Nova Scotia, New Brunswick, and the Province of Canada into a single nation under self-governance, while remaining part of the British Empire with Queen Victoria as the head of state. Regarding the question of who signed the BNA Act of 1867, the answer is c) Queen Victoria.
Key figures like Sir John A. Macdonald, Sir George-Étienne Cartier, and Sir Alexander Tilloch Galt were instrumental in the confederation process, and MacDonald became Canada's first Prime Minister. However, it was Queen Victoria who formally assented to the legislation, thus enacting it. The Act provided the constitutional framework for the establishment of Canada, facilitating the creation of a national defense and the construction of the transcontinental railroad, the Canadian Pacific Railroad, which was completed in 1885.