Why do MP3 files provide music of inferior quality than WAV files?
A. Because MP3 files take up 12 times more space than WAV files do
B. Because MP3s are designed to save space and are compressed
C. Because WAV files are more compressed and smaller than MP3s
D. Because people who put their music on MP3s are amateur artists

B. Because MP3s are designed to save space and are compressed

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."

well it depends i think people around the world are coming around to gay marriage. but if you are talking abortion then wow, so much to talk about. such as men thinking they have the right to choose if women can, the fact there are health concerns if the women can't get one, and many more arguments to discuss. so i would definitely say abortion would be a much more interesting topic.