Marcie’s family takes a trip to the beach. They observe many features along the shoreline, including sea stacks and sea arches. These features are made of granite, a very hard rock. It takes many years and a huge amount of wave energy for a sea arch to fall, forming a sea stack. The sea arch illustration on the left is an arch made of rock, while the sea stack illustration on the right is two columns of rock with a space in between.

Marcie believes that the sea arch was once part of a mountain. Which sentence explains how the mountain was formed?

A. Plates moved apart to form it.
B. Volcanic lava hardened to form it.
C. Tectonic plates collided to form it.
D. Sand was deposited to form it.