Which cloud type is typically associated with overcast skies but generally does not produce halos?

The cloud type that is typically associated with overcast skies but generally does not produce halos is altostratus clouds. These clouds are generally uniform in appearance and cover the sky, resulting in overcast conditions. While they can create some light filtering effects, which may produce a dimmed sunlight appearance or even a sun that looks vaguely outlined, halos—often caused by ice crystals found in higher cirrus clouds—are not characteristic of altostratus clouds.

Cirrocumulus clouds, which are high and often patchy, can have a halo effect due to ice crystals, while stratus clouds, although they produce overcast conditions, generally do not lend themselves to halo formation, particularly because they are composed more of water droplets than ice crystals. Cumulonimbus clouds, being towering and associated with severe weather, can also produce halos if certain conditions for ice crystals are met, but they are more known for thunderstorms rather than consistent overcast skies. Thus, the distinct characteristics of altostratus clouds—and their lack of halo production amid their overcast nature—make them the correct choice.