What statement about the age of gang members is false?

What statement about the age of gang members is false?
 
  a. Traditionally, most members of offending groups were usually no more than a few years apart in age.
  b. Because members are staying in gangs longer than in the past, it is believed the average age of gang members has been increasing.
  c. The changing structure of the U.S. economy has allowed former gang members to leave the gang for higher-paying jobs.
  d. Criminal records acquired at an early age quickly lock gang members out of the job market so that remaining in a gang becomes an economic necessity.