Final answer:
The number of adolescents who say they have never had sexual intercourse increased by 20% from 1991 to 2007, reflecting changing sexual attitudes and a preference among American adults for comprehensive sex education over abstinence-only programs.
Step-by-step explanation:
The correct option for the question of how adolescent sexual behavior has changed from 1991 to 2007 is B) increased; 20%. This data hints at evolving sexual attitudes amongst young people. Despite the increase in liberal views on topics like unmarried females having children, the desire for monogamy remains strong. These trends are mirrored in sex education debates, where there's a shift towards recognizing the importance of teaching about safer sexual practices and contraception alongside, or in place of, abstinence-only education. Research indicates that most Americans favor educational approaches that reduce unintended pregnancies and the spread of sexually transmitted infections more effectively than abstinence-only programs.