The main conclusion is a law that prevents minors buying headphones.


a. percentage of federal legislators who would vote for a bill that prohibits the sale of headphones to minors.
Irrelevant.

b. The number of adolescents who use headphones on a regular basis but do not suffer from hearing loss.
Irrelevant, because it is concluded in the premise that adolescents are 3 times likely to suffer hearing loss anyway

c. The extent to which other common adolescent behaviors contribute to hearing loss.
Premise has already concluded that adoescents who use headphones regularly have hearing loss issues in the future- the argument is on headphones.

d. The percentage of parents who would refuse to purchase headphones for their adolescent children.
Law will prohibit sale of headphones to minors, so what is the possibility of a parent, an adult, who can legally buy the headphone and give it to a minor? Correct.

e. The difference in level of hearing loss between adults who have used headphones since adolescence and those who began using headphones as adults.
Irrelevant as it is comparing 2 different demographics.