Which of the following is a primary source of law?

• A. Case law
• B. Legal magazines
• C. Market prices
• D. Case summaries

Answer: (A)

Primary sources of law are the actual rules that govern society, produced by official authorities. Case law is a primary source because court opinions create and state the legal standards and precedents that guide future decisions. When a court decides a case, its ruling interprets statutes and constitutional provisions, and the written opinion becomes binding authority within the jurisdiction.

Legal magazines and case summaries are secondary sources—they explain, analyze, or summarize the law but do not themselves establish binding rules. Market prices aren’t legal authorities at all. So, the best answer is case law, since it provides the original, authoritative legal rules that courts apply.