Questions: The number of U.S. Courts of Appeals in the federal court system is:

The answer is: 13.

Explanation for each option:

1. 52: This is incorrect. There are not 52 U.S. Courts of Appeals in the federal court system. The number 52 might be confused with the number of states plus territories, but it does not apply to the federal appellate courts.

2. 13: This is correct. The U.S. federal court system is divided into 13 Courts of Appeals, also known as Circuit Courts. These include 11 regional circuits, the D.C. Circuit, and the Federal Circuit.

3. 4: This is incorrect. There are more than 4 U.S. Courts of Appeals. This number might be confused with the number of levels in the federal court system, but it does not represent the number of appellate courts.

4. 94: This is incorrect. There are 94 U.S. District Courts, which are the general trial courts of the federal court system, not the appellate courts.

In summary, the U.S. Courts of Appeals are organized into 13 circuits, each serving a different region or specialized area of law.