Which factors keep people from settling near the rocky mountains?

Agriculture can prove extremely difficult to maintain on a rocky mountain and with such poor infrastructure it is also difficult to import goods on a JIT (Just In Time) sort of basis where you receive these goods as you need them. Infrastructure also includes communication and other services and with such a technologically developed era we depend on technology and this can deter a lot of people from settling in these regions, additionally the wildlife in these regions consists greatly of predators which can be deemed a threat to habitants who are unprepared. The sheer abundance of wildlife and non industrial landscapes can also mean that people will not want to live in these regions

Answer islamic scholars made advancements in technology, literature, philosophy, mathematics, astronomy, and the arts during this time period;

The answer is d) rift