Which federal court would be the first to hear a criminal case?

The correct answer is B. a district court.

District courts are the trial courts of the federal court system and are the first to hear criminal cases. They handle a wide range of cases, including those involving federal laws. After the district court, any appeals would go to the Court of Appeals, and eventually, some cases can reach the Supreme Court. If you have more questions or need further explanation, feel free to ask!