Why are volcanoes and volcanic activity a good example of system interactions?

Because volcanoes can release large amount of particulate matter into the atmosphere with the effects of the Earth's spheres, such as biosphere, geosphere, and hydrosphere.

Explanation:

Volcanoes (an event in the geosphere) release a large amount of particulate matter into the atmosphere. These particles serve as nuclei for the formation of water droplets (hydrosphere). Rainfall (hydrosphere) often increases following an eruption, stimulating plant growth (biosphere).

i think the answer is b.