Clay was crushed and frozen under a glacier. Lava from a volcano cooled quickly in water. River sediments were slowly compacted and cemented together. Mineral deposits hardened into solid rock in underground caves.
I gave my students this multiple choice question: A student observed a rock made up of many small particles of sand arranged in light-colored layers and dark-colored layers. Which of the following statements describes how this type of rock most likely formed?

Only one answer is correct among these 4 choices:
- Clay was crushed and frozen under a glacier.
- Lava from a volcano cooled quickly in water.
- River sediments were slowly compacted and cemented together.
- Mineral deposits hardened into solid rock in underground caves.

Could you tell me which one is correct?

River sediments were slowly compacted and cemented together.