With Its Ruling in Reno V

With its ruling in Reno v. ACLU in 1997, the Supreme Court invalidated a federal law passed to protect minors from "indecent" and "patently offensive" communications via the Internet. What was the Court's rationale in its invalidation of the federal law?

A) The Internet is impossible to police.
B) To restrict Internet speech in the United States would also restrict it in other countries.
C) In denying minors access to potentially harmful speech, the law suppressed a large amount of speech that adults have a constitutional right to receive.
D) The Internet is no standard group or vehicle by which to define "decency," much less to enforce the standard.
E) Control of Internet speech is a role for the state governments, not the federal government.