Which of the following is a chemical change?
A. Sulfur and iron filings are mixed together in a beaker at room temperature.
B. Sulfur and iron filings are mixed together and the iron is removed with a magnet.
C. 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.
D. A mixture of sulfur and iron filings are placed in carbon disulfide, the sulfur dissolves, leaving iron behind in the bottom of the beaker.