The magma marked with C, is a felsic (rhyolitic) magma. This type of magma has high content of silica, making it highly viscous, and it also has high content of gases. The high content of gases comes from the high viscosity, as the gases are trapped inside the magma and can not get out of it. This results in eruptions of explosive or effusive type. When the magma rises, the temperature and pressure change, with results in explosion of the trapped gases in the highly viscous magma. Through this explosion, lot of pyroclastic material is shot out of the volcano in the surrounding area, making it very dangerous for everything in its surrounding area.
