Because economy within a certain region will be heavily depended on what resources that are available in that region.
Since the Arabian Pennisula do not possess a good climate to produce agricultural products, it's almost impossible for agricultural sector to flourish in this region, and therefore they focused their economy on things such as oil, silk, zaitun, etc.
Answer: There are no Greeks because you didn't put any options
Explanation: Can you please put the question on here, and edit, so we can see which of the "following" are Greeks??
It would be A. Examples of civilizations in the Arabian Peninsula hope his helps
