the mass the volume the temperature the state of matter
I gave my students this multiple choice question: A beaker containing 50 milliliters of ice is placed on a windowsill. After several hours, the ice melts. What property of the ice did not change when it melted?

Only one answer is correct among these 4 choices:
- the mass
- the volume
- the temperature
- the state of matter

Could you tell me which one is correct?

the mass