Which of the following justices was a well-known loose constructionist?

A well-known loose constructionist among the options provided would be Sandra Day O’Connor. Loose constructionism is an interpretive approach that allows for a broader interpretation of the Constitution, while Thomas Jefferson, although he had some loose constructionist views, is often associated with stricter interpretations regarding the Constitution. Clarence Thomas is known for a more strict constructionist approach, and George Washington is not typically categorized as a constitutional interpreter in these terms. Therefore, the best answer is A. Sandra Day O’Connor.