C because a compound sentence is when you have once sentence, but it can become two. it is separated by commas (,)
Theory of plate tectonics states that Earth's surface the upper mantle an crust, was once made up of enormous rock plates that broke into smaller pieces approximately 300 million years ago and These smaller broken plates form more fluid rock surface in the mantle. as Time passed the plates move and morph into natural land boundaries. This explains natural land phenomena, such as earthquakes and tsunamis.
Answer:
he often complains to his mother after school
