Answer:
B. Chemical change because mass was lost
Step-by-step explanation:
When experiment was done then at the end, the state of the specimen did not changed but the mass varied this certainly means it is a chemical change.
A chemical change can be describes as a change after which the properties of the reactant get changed and can never be replenished again.
It is termed as irreversible reaction as the original reactant cannot be taken out of the final product.
Mass of the reactant is not equal to the mass of the product and state is still the same which means there must be some chemical reaction that have taken place which is responsible for this loss of mass.