Answer:
B. This is a decomposition reaction and the mass reading will stay the same as time progresses,
Step-by-step explanation:
Decomposition reactions are when one reactant decomposes (breaks down) into two or more products. They follow the general form of:
AB --> A + B
The law of conservation of mass tells us that when a chemical reaction takes place, no mass is created or destroyed but transforms from one form to another. You can see from the diagram that you have the same number and type of atoms on each side of the reaction.