In many areas "atoll" clouds (clouds of vertical development) are produced over small islands. These are the result of __________.

Correct Answer: Option D — rising air currents produced by the warm islands

Daytime solar heating over landmasses warms the air above the island, creating thermal convection currents. This rising buoyant air condenses moisture at altitude, forming localized cumulus clouds of vertical development commonly referred to as atoll clouds.