Answer:
Correct answer is The temples were built as tombs for pharaohs.
Step-by-step explanation:
Last option is correct, as temples were not tombs for pharaoh. Those were pyramids.
Pyramids were built of mud brick, and most of them as indicated were built during the Old and Middle Kingdom. The most famous, though, were built during the period of Old Kingdom.
On the other side, even they historians are amazed and are asking themselves how was it possible that this structures were built a couple of centuries ago.