Final answer:
Al Capone was sentenced to 11 years for tax evasion, despite his extensive criminal operations during the Prohibition era. He eventually served part of his sentence in Alcatraz.
Step-by-step explanation:
Al Capone, also known as "Scarface", was a notorious figure during the Prohibition era, heading an extensive criminal organization called the Chicago Outfit, also referred to as the Chicago Mafia. Capone's illicit activities, which included bootlegging, prostitution, and gambling, brought in immense profits, reportedly over $100 million annually.
Despite his broad criminal enterprise, it was tax fraud that led to his downfall. In 1931, Al Capone was convicted of tax evasion and sentenced to 11 years in prison. He served part of his sentence at the infamous Alcatraz prison in California.
The correct answer to the multiple-choice question, "How long was Al Capone sentenced for," is c. 20 years.