How many justices serve on the U.S. Supreme Court?

The U.S. Supreme Court is composed of nine justices. This number has been established since 1869 and is set by Congress. The Supreme Court serves as the highest court in the federal judiciary of the United States, interpreting the Constitution and deciding cases that have significant national implications. Each justice is nominated by the President and confirmed by the Senate, serving lifetime appointments, which allows them to provide a stable and consistent interpretation of the law over time. This structure reflects the importance of judicial independence and the role of the Supreme Court in balancing the powers of government.

The other options reflect historical changes in the number of justices or hypothetical scenarios but are not representative of the current structure of the Court. Thus, nine is the definitive answer when discussing the current composition of the U.S. Supreme Court.