When a single salt crystal is added to a cool liquid, large crystals form. Which statement about the original cool liquid is correct? A. The liquid is a pure substance because it was uniform before the crystal was added.

B. The liquid is a pure substance because it was made up of a single compound.

C. The liquid is a homogeneous mixture because the substance that formed the large crystals was uniformly dissolved.

D. The liquid is a heterogeneous mixture because the crystals can be easily separated from the liquid.