Question

mr. garcia uses magnets to hold a poster on a steel filing cabinet because a main component of steel is
iron.
carbon.
plastic.
glass.

Explanation:

Steel is an alloy primarily composed of iron (along with a small amount of carbon). Magnets attract ferromagnetic materials like iron, so the main component of steel that allows it to be attracted to magnets is iron. Carbon is a minor component in steel, while plastic and glass are not components of steel.

Answer:

A. iron