Relic Boundary is the correct answer :)
The last "hot house" or period of increased temperature occurred during the time of dinosaurs. The temperature in today's world is rising slowly but it is still miles away from the temperature that dinosaurs had to face during "hot house". I hope that the answer comes to your help.
From an overall perspective, A would be the best answer. Since the Nile River has always been one of the biggest rivers in history, it would most likely sustain life for the people. As well as the mediterranean, people for thousands of years relied on the Mediterranean Sea for their food and even their transportation.