Explanation:

- Tyrant: A ruler who uses power oppressively or unjustly.

- Option 1: Patron: Someone who supports or champions a person, activity, or cause, often with money or influence.

- Option 2: Benefactor: Similar to a patron, this is someone who gives support, typically financial, to someone or something.

- Option 3: Champion: A defender, supporter, or advocate of a cause or individuals.

- Option 4: Rival: A person or thing competing with another for superiority or the same objective.

The most appropriate antonym for tyrant is one who does not oppress or dominates but rather supports or assists. None of the options are the perfect opposite of a tyrant, but we can see that:

- Option 1 could fit loosely since it refers to supporting rather than dominating.

Thus, if we have to choose the closest antonym:

- Option 1: Patron