How might the evidence the author provides in "the completely free market" affect the overall argument being made?

a. the author has never illegally downloaded music, so he or she doesn't understand the topic well enough to comment on it. b. the author uses outdated information to present his or her argument. c. the author doesn't provide any real evidence of facts and figures; it's all opinion-based. d. the author's evidence only comes from one source—an insider in the music industry—which makes the article biased.