Question

eruptions of hotspots beneath continents are extremely explosive because
a both a and c
b a plume must be massive to penetrate continental crust
c the eruptions occur frequently
d the eruptions release enormous amounts of mafic lava

Explanation:

Hotspot eruptions under continents are explosive because the magma interacts with thick continental crust, and they also tend to release large volumes of silica-rich (not mafic) lava. Additionally, the massive mantle plume needed to break through thick continental crust contributes to the explosive nature, and these eruptions can occur with notable frequency. Thus both option b and c are correct, so option a is the right choice.

Answer:

a. Both A and C