Altostratus clouds are considered part of which height group?

Correct answer: Middle clouds

Correct answer: B. Cloud classification uses both appearance and height. The prefix “alto” is commonly used for middle-level clouds, so altostratus is a middle cloud. Altostratus usually forms a broad, fairly uniform sheet at middle altitude and may cover much of the sky. It can be associated with a large weather system and may thicken before prolonged precipitation, although the name itself identifies its general height group rather than guaranteeing rain. B is correct because altostratus belongs to the middle-cloud group. A is wrong because low clouds occur nearer the surface and include forms such as stratus and stratocumulus. C is wrong because altostratus is mainly a layered sheet, not a purely vertical cloud. D is wrong because fog is a cloud at or near the ground, whereas altostratus is elevated. Memory cue: “alto” in cloud names usually signals middle level; “cirro” signals high level.