Your question seems to be a bit muddled. "Horse latitudes" are associated with the "Subtropical High Pressure" system.
You wrote the first two words of your answer already!
Answer:
Option C => They were deposited by glaciers.
Explanation:
Whenever we have a polished bedrock it is very important to know that the landscape can be found in places that are full of or has glacials. It is a process or phenomenon known as Glacial polish that causes large boulder in the area(even after the glaciers has melted). Therefore, option (C) is the correct Option in the question above.
Note that, the term " Glacial polish'' simply means the process in which the surface of bed rocks are grinded by graons and many or several pieces of rock.
The movement is called convection, where warm material rises, then cools, then sinks back down.
