Which of the following boxers did not win a gold medal before becoming a professional boxer?

Evander Holyfield was not a gold medal winner before becoming a professional boxer. Holyfield (born October 19, 1962) is an American former professional boxer, who held the undisputed world championship in both the cruiser weight and heavy weight divisions. Because of his abilities as a fighter, he earned the nickname "The Real Deal". He is the only four-time world heavyweight champion, having won the WBA, WBC, IBF and lineal titles in 1990; the WBA, IBF and lineal titles again in 1993; and WBA and IBF titles in 1996. He won the WBA title for a fourth time in 2000.

As an amateur, Holyfield represented the United States at the 1984 Olympics, winning a bronze medal in the light heavyweight division. He turned professional at the age of 21, moving up to cruiser weight in 1985. He won his very first world championship in 1986 when he defeated Dwight Muhammad Qawi for the WBA title.