Answer: D. U.S. District Court
Step-by-step explanation: The federal trial court is called the U.S. District Court. It is the lowest level of the federal court system and is responsible for hearing both civil and criminal cases. The U.S. is divided into 94 judicial districts, each of which has at least one U.S. District Court. These courts handle a wide range of cases, including federal law violations, bankruptcy matters, and civil disputes between individuals or businesses.
It's important to note that the U.S. District Court is different from the other options mentioned. The Federal Circuit Court is a higher level appellate court that primarily hears patent and other specialized cases. The Court of Claims is a specialized court that handles claims against the U.S. government, and the Federal Trial Court is not a recognized term used to refer to a specific court.