Answer:
A. Highly viscous and associated with violent eruptions
Explanation:
Most silica rich magma have high viscosity and huge amount of trapped gases within them. As they continue to upwell and expand, the gases causes violent eruptions near Volcanoes. Most granitic/rhyolitic magma are silica rich.
Answer: Option (A)
Explanation: Silica rich magma are those in which the magma has more than 65 % of silica content. The higher the silica content, the higher is its viscosity i.e viscosity of a magma is directly proportional to the silica content of magma.
This highly viscous magma inside the volcanoes moves sluggishly and mostly gets concentrated in the vents and seals them. With time, when the pressure exerted by the magma is too high, it creates violent eruptions through the vents.
Thus, the correct answer is option (A).
