Hello there! The answer is description of a character’s physical traits.
Direct characterization is when an author directly tells you something about a character. Indirect characterization is when you find things through what a character does. Out of the options given, description of a character’s physical traits is the only one that straight up tells you something about the character.
With a description of a character’s actions, description of a character’s interactions, or a description of a character’s thoughts you get a characterization through what they do, meaning it is not a direct characterization, meaning these are incorrect.
I hope my answer was helpful, have a great rest of your day! :)