Explanation:

- Option 1: "in extracurricular activities."

- This is grammatically correct. It correctly follows "enrolled".

- Option 2: "Regardless of class, income or race,"

- This is correctly formatted as an introductory phrase setting the context.

- Option 3: "should enrolled"

- This is incorrect. The correct form should be "should be enrolled" because "should" requires the base form of the verb, so it should be followed by "be" and then "enrolled".

- Correct Answer

- Option 4: "children who are bored after school"

- This is a properly structured relative clause that accurately describes the nouns.