C) They believed Earth to be much younger than current estimates.
Explanation:
The proponents of the 18 and the 17th centuries believed that the earth was shaped by a strong and a violent forces such as the erosion that created the earth's geologic features and had a recent origin.
The climate in Saudi Arabia, Iraq, and Iran is mainly Desert.
Those places are located around the Middle East area and the Middle East is covered in dry hot sand so it'll make sense that Saudi Arabia, Iraq and Iran is a desert.