Question Wording
I like Jennifer's idea to give participants the option "none of the above" because if we choose to instead allow them to have the choice of not answering at all it could effect how valid our results may be. In order to accurately measure the influence of media on political participation we should also examine the different forms of media which were available then ('97) in comparison to the ones available now. So maybe instead of Has there been an increase in the availability of the news we can ask "Has the availability of new forms of media (Facebook, Twitter) effected your level of political participation?" or "Do you feel new forms of media have influenced you to engage more in the electoral process?"
I also agree with Chris that since we are looking at a certain time frame to support our hypothesis we do need to target people who were eligible to vote since '97 to clarify that their lack of participation was not due to age restrictions.