Answer:
A) A mixture of sulfur and iron filings are heated until the contents glow red and the appearance of the mixture changes. A magnet can no longer remove iron filings.
Step-by-step explanation:
Chemical change is a change which brings a change in the composition of the substance.
When sulphur and Iron fillings are heated a chemical reaction takes place which leads to the formation of FeS.
FeS is a new substance which has completely a different property than that of Iron.
Iron has magnetic property gets attracted to the magnet.
FeS formed is no longer attracted to the magnet. A magnet can no longer remove iron filings because all the iron have been converted to FeS.