Where should the past perfect tense be used in this example?<br/><br/>'He finished his exam when his friend <b>had only got</b> to the 5th question'<br/><br/>A) He went well in his exam. He finished it when his friend <b>had only got</b> to the 5th question.<br/><br/>B) He went well in his exam. He <b>had finished</b> it when his friend <b>had only got</b> to the 5th question.<br/><br/>C) He went well in his exam. He <b>had finished</b> it when his friend only got to the 5th question.<br/><br/>Is A the best one, as it at least does not change the meaning of the sentence despite not shifting back in tense?<br/><br/>Thanks.