Final answer:
Chlorofluorocarbons (CFCs) are the most efficient at trapping heat, with a global warming potential in the thousands, much higher than other greenhouse gases such as carbon dioxide, methane, nitrous oxide, and ozone.
Step-by-step explanation:
The most efficient greenhouse gas at trapping heat, based on their global warming potential (GWP), is not carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), or ozone (O₃), but chlorofluorocarbons (CFCs). CFCs have a much higher GWP because of their ability to absorb and re-radiate infrared energy and their very long residence time in the atmosphere. They are synthetic gases, and like other greenhouse gases, they contribute to the enhanced greenhouse effect by trapping heat that would otherwise escape into space.
While methane is about 28 times and nitrous oxide 298 times more effective than carbon dioxide at absorbing infrared radiation, CFCs have GWPs in the thousands, far surpassing those of naturally occurring greenhouse gases. This extreme efficiency makes them the most potent among the options given in the question regarding their heat-trapping capabilities.