CORRECT answer is option 3, i.e., requested.The SENTENCE suggests that the blank must contain a verb that can be used with the PREPOSITION 'for'.The appropriate verbs here can be 'asked for' or 'requested for', given the context.Since it can be IMPLIED that the student is communicating with the authority, 'requested for' would be more suitable for the given blankThus the correct sentence is The student requested for a refund of fees.