Final answer:
The majority of Aboriginal people in Canada identify as First Nations, comprising approximately 50% of the Aboriginal population, making option C (50%) the correct answer to the question.
Step-by-step explanation:
The question pertains to the percentage of Aboriginal people who are classified as First Nations in Canada. According to the information provided, there are over 1.5 million people in Canada who identify with one of the three Indigenous groups: First Nations, Inuit, and Métis.
With over 630 First Nation groups representing 50 Nations and languages, and given that the overall Aboriginal population is about 1.2 million, it is reasonable to deduce that the majority of the Aboriginal population identifies as First Nation. Hence, the correct answer to the question would be C. 50%. This is consistent with the detailed information, which does not offer a specific percentage but does indicate that the First Nations are the largest of the three groups mentioned.