Volcano a erupts rocks with sio2 content ranging from 49% to 52% whereas volcano b, 100km away, erupts materials with sio2 content of 62-68%. which statement best characterizes these two volcanoes?

a. both volcanos are shield type volcanos that are characterized by quiet eruptions.
b. both volcanos are violent, explosive volcanos that spread ash continent wide.
c. volcano a is likely to be a supervolcano with violent eruptions, whereas volcano b is probably a shield volcano with quiescent eruptions.
d. volcano a is probably a shield volcano with typically quiescent eruptions, whereas volcano b is likely a stratovolcano characterized by violent, explosive eruptions.