Final answer:
The passage emphasizes the hazards associated with incorrect or unsafe use of fireplaces and implies that regular inspections are necessary to prevent these risks and maintain safety. Option C.
Step-by-step explanation:
The passage provided hints at several dangers associated with fireplace usage, leading to the implied main idea that fireplaces should be inspected regularly.
This idea is derived from the various issues outlined such as potential bird nests in chimneys causing smoke back-up, small cracks letting flames escape and come in contact with house walls, the risks from burning toxic materials, and the danger of ash and sparks potentially igniting nearby flammable objects.
Regular inspection could prevent these hazards and ensure the safe enjoyment of fireplaces. Educational insights such as the toxicity of carbon monoxide and the health implications of burning wood and other materials reinforce the importance of maintaining a safe fireplace environment.
So option c is correct.