Final answer:
Thomas Jefferson and his followers opposed Adams's judicial appointments as they believed that the appointments were unconstitutional. The correct answer is option B.
Step-by-step explanation:
Thomas Jefferson and his followers opposed John Adams's last-minute appointment of new federal judges mainly because they believed that the appointments were unconstitutional. Adams made these appointments to preserve the Federalist agenda before Jefferson took office. However, Jefferson and his supporters saw this as an attempt by the defeated Federalist party to entrench itself in the government. The controversy over these appointments led to the landmark case of Marbury v. Madison, where the Supreme Court established its power to review and strike down unconstitutional laws.