Final answer:
The source of law in Canada that is not considered a formal source is Public opinion. The recognized sources include Common law, Civil Code of Quebec, and Royal prerogative.
Step-by-step explanation:
The source of law in Canada that is NOT considered a pillar of the legal system is B) Public opinion. The recognized sources of law in Canada include A) Common law, which is developed by judges through decisions of courts based on past precedents. Additionally, C) Civil Code applies in the province of Quebec and is a comprehensive set of written laws that cover various aspects of private law. Lastly, D) Royal prerogative refers to the powers and privileges accorded to the Crown, which are part of the legal system. Public opinion, while influential in many aspects of society and politics, is not a direct source of law.