Answer:
The correct answer is D. The two main types of federal courts are constitutional and tribunal.
Explanation:
The federal Judiciary of the United States is organized by Article III of the United States Constitution.
Said Article establishes the existence of a Supreme Court, which will be the head of the nation's judicial system, and whose functions, composition and method of appointment are provided by the Constitution itself. Therefore, the Supreme Court is a constitutional federal court, as this norm explicitly creates and regulates it.
Also Article III itself establishes that Congress may create lower courts, which will be in a lower rank than the Supreme Court. These courts are called tribunals.
