Which of the following is true about Thurgood Marshall?
A.He was the first African-American to serve on the United States Supreme Court
B.He convinced the U.S. Supreme Court that the policy of "separate but equal" as defined by the Plessy v. Ferguson case was unconstitutional
C.As chief counsel for the NAACP he was an avid crusader for equal rights
D.All of the answer choices are correct