Which sentence from Passage 2 does the most to define the key idea of the passage? "Cristian liked to hear poetry, but really enjoyed it when people listened to his own stories from earlier days." (paragraph 9) "'I got the feeling he was a sad man,' Carol tells Choices." (paragraph 9) "Along the way, Carol discovered how fulfilling it is to help others." (paragraph 10) "She also found out something else: Volunteer work can help positively shape a teen's future." (paragraph 10)