Final answer:
In the context of defamation law, the Supreme Court stated in Gertz v. Robert Welch, Inc. that a person commonly becomes a public figure by being involved in a public controversy.
Step-by-step explanation:
The Supreme Court indicated in Gertz v. Robert Welch, Inc. that a person most commonly becomes a public figure by b) being involved in a public controversy. This case, along with others like New York Times v. Sullivan, which required public figures to prove 'actual malice' in defamation cases, has shaped the legal landscape regarding freedom of speech and the protections afforded to individuals in the political arena. This distinction between private individuals and public figures affects the level of proof necessary to prevail in a defamation lawsuit, acknowledging the value of critical speech in a democratic society.
Answer: b) By being involved in a public controversy