Why do many earthquakes and volcanoes occur along the Ring of Fire?

Explanation:

The abundance of volcanoes and earthquakes along the Ring of Fire is caused by the amount of movement of tectonic plates in the area. Along much of the Ring of Fire, plates overlap at convergent boundaries called subduction zones. As rock is subducted, it melts and becomes magma

b would be the right answer

it cools slower in the earth meaning the crystals have more time to form than lava on the surface