Why Is Milk Used as a First-Aid Remedy for Someone

Why is milk used as a first-aid remedy for someone who has swallowed a heavy-metal poison?

A) The metal taste of the poison is removed by consuming milk.
B) Milk will cause the person to vomit and expel the poison.
C) Calcium in milk will render the poison harmless.
D) The poison acts on the protein in the milk rather than on the gastrointestinal tract.