Explanation:

- Common Law : This is the correct answer. It is the legal system that began in England and is now used in the United States. It relies on judicial decisions (precedents) instead of just written laws.

- Trial Court: This is a court that hears cases first, where the facts are decided. It is not a system, but rather a type of court.

- Decisions (courts): These are outcomes or judgments issued by courts. They are a component of common law, but not the name of the system itself.

- Appellate Court: This is a higher court that reviews decisions made by trial courts. Like trial courts, it’s part of the system but not the name of the system.