abhimahna
Shouldn't the answer be B here? War happened earlier and then Timmy learned about it. As per OA, looks like both could be used with same time frame(tenses). Please suggest.
Past perfect is used only when it is required to clarify the sequence. Following is an excerpt from Manhattan SC guide:
Do not use the perfect tenses when the simple tenses will do. The GMAT prefers simplicity.
Wrong: Joe LEARNED about an epoch in which dinosaurs HAD WALKED the earth.
Right: Joe LEARNED about an epoch in which dinosaurs WALKED the earth.
In the first example, the Past Perfect had walked is unnecessary. Although the action had walked does take place earlier than the action learned, the earlier action does not have a direct bearing on the context of the later action. The sequence of time does not need to be clarified or emphasized. Thus, the Past Perfect is considered wrong in this context.