Why Did the Supreme Court Rule the Communications Decency Act

Why did the Supreme Court rule the Communications Decency Act unconstitutional?

A) state laws that make flag burning a crime are too lenient
B) Because it violated the First Amendment's right to freedom of assembly.
C) Because it granted too much authority to the executive branch and, therefore, violated the separation of powers.
D) Because it attempted to protect children by suppressing speech that adults have a constitutional right to receive.
E) Because it imposed penalties that were too severe for certain forms of hate speech.