Spot Advertisements Are Useful Because They

Spot advertisements are useful because they

A) permit a candidate's message to be delivered to a target audience before people can tune out.
B) are essentially free of charge, because the media needs to fill the "spot."
C) are funded through a loophole in campaign finance laws.
D) are the best means for an audience to get the most information about the policy preferences of candidates, rather than the candidates' personalities.
E) are funded by nonpartisan organizations rather than candidates.