A. requested: This is the correct option. "Requested" is the past tense form of the verb "request," which means to ask for something formally or politely. In this sentence, the use of past tense indicates that the student asked for more answer sheets at some point during the examination. B. requested for: While "requested" is correct, adding "for" after "requested" is unnecessary. In English, the verb "request" is often followed directly by the object being requested without the need for a preposition like "for." For example, "He requested assistance" is correct, while "He requested for assistance" is less common and not as grammatically correct. C. requests for: This option uses the present tense form of the verb "requests," which is not suitable in this context. The sentence is describing an action that occurred in the past (during the examination), so the past tense "requested" is more appropriate than the present tense "requests." D. request: This option is incorrect because "request" is the base form of the verb, and it does not indicate past tense. The sentence requires a past tense verb to match the context of the action happening during the examination.