D. A change in a substance with no new substances being formed
There are 2 ways a substance can change, physical changes and chemical changes. In all changes, physical or chemical, mass is always conserved.
Physical vs. Chemical
The main difference between a physical and chemical change is the substance at the end.
New substances are only created by chemical changes. Additionally, only chemical changes break apart bonds. Physical changes maintain the same compounds and elements, so bonds are not broken.
Examples of Physical Changes
Physical changes do not change the actual substance, but they can change the form of the substance.
All of these change the state of matter or shape of the substance, but not the chemical makeup.