sand separated from water by filtering water evaporating from a puddle a rock being eroded by wind a nail rusting in water
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which is an example of a chemical change?
Possibilities:
- sand separated from water by filtering
- water evaporating from a puddle
- a rock being eroded by wind
- a nail rusting in water

a nail rusting in water