Final answer:
The Constitutional Act of 1791 was the Act that for the first time in Canada, established legislative assemblies elected by the people, making B the correct answer.
Step-by-step explanation:
The Act which granted, for the first time in Canada, legislative assemblies elected by the people was the Constitutional Act of 1791. Option B is the correct answer. This Act divided the colony of Quebec into Upper and Lower Canada, each with an elected legislative assembly, the beginnings of a representative government.
The Constitutional Act of 1867, known as the British North America Act at the time, established the Confederation and the federal structure of government in Canada, but it did not grant legislative assemblies for the first time.
The Constitutional Act of 1982 brought significant changes to the Canadian constitution, including the addition of the Charter of Rights and Freedoms. The Constitutional Act of 2010 does not exist, making it an incorrect choice.