Step-by-step explanation:
Attorney Clarence Darrow is known for defending Option 1: Unpopular persons and causes.
Clarence Darrow was a prominent American lawyer known for his defense of unpopular clients and causes. He was involved in several high-profile cases, including the Scopes Monkey Trial in 1925, where he defended a teacher accused of teaching evolution in a Tennessee public school. Darrow was known for his skills as a defense attorney and his commitment to civil liberties and social justice.