One of the factors that determine the weather patterns across South America is its geography. Among the reasons falling in this category is the elevation. Thus, the answer is letter B. The weather becomes colder as the altitude increase.
The factor that helps to determine weather patterns across South America is elevation. The correct option among all the options that are given in the question is the second option or option "B". There might be some other factors as well but this is the major factor for determining the weather patterns of South America.
