During an experiment, iron powder and sulfur powder were heated together to form a black mass. it was observed that a magnet, when brought near the black mass, did not attract the black mass. which of the following correctly justifies the observation?
b. the black mass is a mixture and retains the properties of iron.
c. the black mass is a pure substance and no longer retains the properties of iron.
d. the black mass is a pure substance and retains the properties of iron.