Which of the following is a primary source of law?

• A. Court opinions only
• B. Executive orders
• C. Legal encyclopedias
• D. Constitutions, statutes, administrative regulations, case law, and court rules

Answer: (D)

Primary sources of law are the binding texts created by the government that actually establish rules and authority. This includes the fundamental documents and rules that shape legal obligations: constitutions set the framework and powers of government; statutes enacted by the legislature establish laws; administrative regulations issued by agencies provide detailed rules and procedures; case law consists of court decisions and opinions interpreting those rules; and court rules govern how cases are handled in the judicial system. Because this option lists the full range of these core, binding sources, it is the best answer.

Other choices are limited or not binding in the same way. Court opinions are important and are a key part of case law, but focusing only on opinions misses other foundational sources like constitutions and statutes. Legal encyclopedias are secondary sources; they summarize and explain the law rather than creating it. Executive orders can be primary sources in certain contexts, but they don’t alone represent the complete spectrum of binding legal texts that establish law.