Is pyroclastic material likely to form from low-viscosity lava or high-viscosity lava?

Explain

Pyroclastic material is likely to form from high-viscosity lava.

Pyroclastic material is a cloud of lava fragments and ash, and viscosity means thickness (so high-viscosity lava will be thicker than low-viscosity lava). When lava has both high viscosity and high gas content, it will expand and erupt, causing liquid and solid rock to fly into the air, thus creating pyroclastic material.