Firefighters determine how long steel has been exposed to heat.

• A. Cooled and humidified
• B. Painted
• C. Exposed to heat
• D. Quenched

Answer: (C)

When steel has been heated, it shows signs produced by that heating. The best indicator for how long it has been heated is simply that the steel has been exposed to heat. Other options describe conditions or actions that can occur after heating (cooling and moisture, painting, or rapid cooling called quenching) and don’t directly prove how long the steel was subjected to heat. So the fact that the steel has been exposed to heat is the key signal you’d rely on to assess prior heating.