Where are earthquakes and volcanoes most likely to occur

C. That is the ring of fire

Almost earthquakes and volcanoes form on fault lines and tectonic plates. This happens due to the plates shifting and moving. When shifting, they can cause a sudden large jolt around the area which is also called an earthquake. That also goes for volcanoes too though because when two plates "smash" into one another, it can create a mountain and/or a volcano. I hope this helped clear things up for you! :D

Are you asking about a street map usage  if so here is your answer  a street map for a very limited area could simply be a bit map or a .jpg image.  but a more general map would probably store the streets as vectors.  but you shouldn't assume that there is one way to do it