Answer:
The correct answer is the deserts surrounding the area, which provided dry, hot air that made for a thriving agricultural climate
Step-by-step explanation:
Namely, two mentioned rivers, that are flowing into the Persian Gulf are the main reason why this area was so fertile. This rivers would overflow the land, thus creating a fine soil, which people used for crops. That is why first option is the wrong one, as Arabian and Syrian deserts didn't affected the Fertile Crescent as this two factors beneath.