What Does It Mean for Mass to Be Conserved

Multiple Choice

What does it mean for mass to be conserved?

A) Mass is neither created nor destroyed in the course of a chemical reaction.
B) Mass is a valuable resource and should not be wasted.
C) Molecules do not degrade under normal circumstances.
D) Atoms sometimes disappear over the course of a chemical reaction.
E) Atoms sometimes appear, disappear, or are changed over the course of a chemical reaction.