請依下文回答第 21 題至第 25 題       Muhammad Ali was born in 1942 and was famous for his unusual boxing style, funny comments, and social justice work. His parents named him Cassius Clay Jr. One day when Clay was 12 years old, his bike was stolen in a local fair. He told a police officer that he would beat up the thief. The officer suggested that he learn how to fight.That officer was actually a boxing instructor and later became Clay’s first boxing coach. When he was only 18 years old, Clay won the gold medal at the Olympics. After that he won his first professional match. His unique style and perfect ring record made him very popular. Before a match, he often guessed for the fans in which round the match would end. In 1964, he boxed against the world heavyweight champion Sonny Liston. Most people thought that Liston would win. However, Clay won, becoming the new world heavyweight champion. After winning, he told the world that he had changed his name to Muhammad Ali. When he retired at 40 years old, Ali had won 56professional wins, and only 5 losses.       During his childhood and youth, black people couldn’t go to the same schools or enter the same restaurants and so on as white people. Even after coming home with his Olympic gold medal, Ali was not allowed to enter white-only restaurants. Because of experiences like that, Ali often spoke about peace and racial justice in public. In 1988 he became the UN Messenger of Peace for his work in developing nations. Like many heroes before him, his legend will live on in the memory of the world.
【題組】21 According to the passage, which of the following topics did Ali often talk about in public?
(A) Heroes and legends.
(B) Learning to fight well.
(C) Avoiding thieves in fairs.
(D) Peace and racial justice.