The answer to this question is actually B.
The question is asking to select the procedure that can show how matter is conserved in physical changes. Removing the core from an apple may be a physical change, but matter is not conserved since something is being lost, the core. Inversely, by melting a piece of ice, no matter is lost and the mass will stay the same before and after the change.
A is incorrect because some matter is also lost there, and C is not a physical change.