The correct answer is B, as the civil rights leader and great-grandson of a slave who was one of the best lawyers of his day, winning 13 of the 15 cases he argued before the Supreme Court was Thurgood Marshall.
Thurgood Marshall was an Associate Justice of the Supreme Court of the United States, serving from October 2, 1967 until October 1, 1991, the first African-American Associate Justice of the country.
Before becoming a judge, Marshall was a lawyer who was best known for his high success in arguing before the Supreme Court, and for winning the Brown v. Board of Education case, a decision that prevented racial segregation in public schools.