Minerals are made of rocks. Crystals are made of rocks. Rocks are made of one or more minerals. Magma is made of solid rock.
I gave my students this multiple choice question: Which statement is true about rocks?

Only one answer is correct among these 4 choices:
- Minerals are made of rocks.
- Crystals are made of rocks.
- Rocks are made of one or more minerals.
- Magma is made of solid rock.

Could you tell me which one is correct?

Rocks are made of one or more minerals.