The answer is A. The main characteristic of a desert is its aridity. Most deserts receive an annual precipitation of ten or fewer inches. Temperatures can't be a defining characteristic of deserts because there are deserts with low temperatures such as those in the polar regions (antarctica). In these regions, water is unavailable because it is completely frozen as ice.
I'm pretty sure that it's A, a little higher because most of the lava runs down the sides of the volcano.
Grids and variables are used to find coordinates. Latitude and longitude coordinates