Answer:
The correct answer is "At a hotspot".
Step-by-step explanation:
A shield volcano is characterized by being comprised in its majority of lava flows. The flow usually is really slow and of low viscosity. Shield volcanos are formed at hotspot locations where magma comes from the bottom to the surface. The formation occurs by layers of magma coming up which later freezes and other layers of magma covering up, which consequently forms the volcano.