Is it safe to leave a hot iron on when no one is around?

The choice indicating that it is a safety hazard regardless of who is present is correct because leaving a hot iron unattended poses a significant risk. An iron generates high temperatures and can easily ignite flammable materials if it comes into contact with them or is left in a position where it can tip over. The potential for fire increases with the duration the iron is left on without supervision.

In situations where people are present, risks can still arise due to distractions or emergencies, and an unattended iron represents a constant threat no matter the circumstances. Thus, even if someone is home, it is still unsafe to leave the iron on without supervision.

Additionally, the other options suggest varying degrees of safety that ultimately underestimate the dangers involved. For instance, the idea that it could be safe only when no one is home ignores the risk to the property and personal safety should a fire start in their absence. Accepting it as acceptable for a short period overlooks the unpredictable nature of fire hazards. Suggesting that only a fire alarm should be present also misrepresents the fundamental issue: the primary concern is the unattended hot iron itself, rather than relying on warning systems after the fact.