Explanation:

- The original sentence is: "The warden punished the students who violates the rules of the hostel."

- The phrase "who violates" is grammatically incorrect because it uses the present tense "violates" for a past action.

- Option 1: "who is violating"

- "Who is violating" suggests the students are currently breaking rules, but the punishment implies past action. This tense mismatch makes it incorrect.

- Option 2: "who violated"

- This option correctly uses the past tense "violated," aligning with the past action of being punished.

- Option 3: "who are violate"

- This option is grammatically incorrect as "are violate" doesn't make coherent sense in English.

- Option 4: No substitution

- Keeping "who violates" doesn't fit the sentence contextually or grammatically.