What type of gas appliance poses a higher risk of fire hazards?

The choice that indicates a higher risk of fire hazards is appliances that are poorly maintained or have blocked vents. This is because neglected maintenance can lead to a variety of issues such as the buildup of combustible materials, malfunctioning components, and inadequate ventilation. Blocked vents can prevent harmful gases from escaping, potentially leading to combustion issues or the accumulation of gases such as carbon monoxide. Additionally, appliances that are not properly maintained may exhibit failures in safety mechanisms, further increasing the risk of fire. Regular maintenance, including cleaning and inspections, is crucial for ensuring that gas appliances operate safely and efficiently, thereby minimizing fire hazards.