I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "Organized crime has long been associated with New York City, beginning with the Forty Thieves and the Roach Guards in the Five Points in the 1820s. The 20th century saw a rise in the Mafia, dominated by the Five Families, as well as in gangs, including the Black Spades. The Mafia presence has declined in the city in the 21st century."?
The answer to this question is:
Which century preceded the 21st century?