The weight of liquefied petroleum gas vapors as compared to air is __________.

Correct Answer: Option D — heavier

Liquefied petroleum gas (LPG) vapors, such as propane and butane, have a vapor density significantly greater than 1.0, making them heavier than air. Consequently, these vapors tend to settle in low-lying areas, bilges, and cargo holds, creating severe fire and explosion hazards.