The answer is a ...........................
Another geologic event that may occur in the dark shaded area on the map is wildfire. The dark shaded area as shown in the map, is an area more commonly known as "The Ring of Fire". Volcanic activity is very common in this area, due to to the many volcanos present.
I would believe it is the Ozone but since it’s not an option the Ferrel Cell is the westerlies and the polar cell is the polar easterlies. So, I would say go with 4! Hope this helps, goodluck! xoxo.