Explanation:

- "Pull someone’s leg" is an idiom commonly used to mean making fun of someone by teasing or joking with them lightheartedly.

- Option 1: "To make someone angry" - This doesn’t align with the meaning of the idiom as it suggests causing someone to be upset rather than playfully teasing.

- Option 2: "To protect someone" - This is not related to the idiom and implies safeguarding or defending.

- Option 3: "To wish someone luck" - This option is also unrelated, as wishing someone luck is more about expressing goodwill rather than teasing.

- Option 4: "To tease someone" - This most accurately captures the intent of the idiom.

Your answer is correct: Option 4 - To tease someone.