Areas immediately to the leeward of mountains have a microclimate with sparse precipitation called a C. rain shadow. As moist air moves landward, it will hit the mountain, which will force the air to move up. As moist air moves higher, it becomes cooler and thus releases its moisture thereby causing rainfall. Once what's left of the clouds passes over the top of the mountain, its moisture has been lost and a rain shadow is formed.
C. They have similar climates, plants, and animals.
I don't know what you mean by "D" climate regions, but the cooler the climate, the more likely permafrost will be found. If the climate is warmer, permafrost won't be found because it will be thawed out.
