age of the rocks way the rocks were formed types of fossils the rocks contain number of minerals found in the rocks
I gave my students this multiple choice question: Rocks are classified as sedimentary, metamorphic, or igneous on the basis of the

Only one answer is correct among these 4 choices:
- age of the rocks
- way the rocks were formed
- types of fossils the rocks contain
- number of minerals found in the rocks

Could you tell me which one is correct?

way the rocks were formed