Final answer:
Statement A that 'an action is not considered a part of freedom of speech' would weaken the argument that burning the flag is protected under the First Amendment by challenging its classification as symbolic speech.
Step-by-step explanation:
The question asks which of the provided statements, if true, would weaken the argument that burning the U.S. flag is a protected form of free speech under the First Amendment. Statement A (An action is not considered a part of freedom of speech) directly challenges the premise that flag burning is a form of expression, and thus, weakens the argument that it is protected by the First Amendment. This is in contrast to the Supreme Court's decision in Texas v. Johnson, which recognized flag burning as symbolic speech under the First Amendment. However, it's important to note that the other options (B, C, D, and E) do not directly address the legal protection of flag burning as a form of speech and hence are less likely to influence the argument regarding its protection under the First Amendment.