The rock a) destroys and create rock b) changes and recyclers earth’s rocks c) happens once every million years d) changes all rocks into igneous rock

B) Changes and recyclers Earth's rocks

In earth, there a 3 kinds of rocks available namely volcanic, sedimentary, and igneous. These diverse rock types can be changed into each other.

Sedimentary rock can wind up molten, transformative or another sedimentary rock, igneous rock can end up volcanic, sedimentary or another changeable rock and molten rock can end up sedimentary, transformative or another volcanic rock. This type of interconversion is explained by rock cycle.  

This conversion occurs through natural phenomenon such as erosion, melting, weathering, effect of heat and pressure, etc.

weathering is the answer.