Who was a Conservative appointed by President Reagan?

The correct answer is Antonin Scalia. Antonin Scalia was appointed by President Ronald Reagan to the Supreme Court in 1986 and is renowned for his strong conservative judicial philosophy, especially his adherence to originalism, which emphasizes interpreting the Constitution based on the original understanding at the time it was adopted.

Clarence Thomas, appointed by Reagan in 1991, is also a significant conservative figure but he was not his first nomination. Anthony Kennedy, appointed in 1988, was considered more of a centrist and often provided the swing vote on the Court, making him less aligned with the solid conservative label in several high-profile cases. John Roberts, appointed by George W. Bush in 2005, is the current Chief Justice and while he is generally conservative, he was not appointed by Reagan but rather by a later president.

This context highlights why Antonin Scalia is recognized specifically for his conservative role during Reagan's presidency.