The correct answers are:
A. debris flow and earthquakes;
C. wild fires;
The volcanoes are a natural occurrences that are vital for the functioning of the planet properly, as they influence all of the spheres, the atmosphere being the most affected of all. But they are also considered as hazards, and not just because of their own hazardous activity, but because they trigger other hazardous events as well.
Because the pressure and temperature are very intense and high, the volcanoes manage to create cracks in the crust, and that triggers the earthquakes to appear. Also, the debris flows are almost a given when a volcano erupts. Because the volcanoes are shooting out lot of material that is with very high temperature, it is very common that wildfires occur and start to burn everything in front of them.