Refer to figure.
Clouds are classified by genus based on their altitude and physical appearance. The ICAO cloud classification system defines three altitude families: 

• High clouds (above approximately 23 000 ft in temperate latitudes)
• Medium clouds (between 6500 and 23 000 ft)
• Low clouds (below 6500 ft)

Cirrus clouds belong to the high cloud family and are found typically between 23000 and 40000 ft in temperate latitudes. They are composed entirely of ice crystals due to the extremely cold temperatures at those altitudes, giving them a characteristic thin, wispy, fibrous or hair-like appearance. 

High thin clouds → CORRECT. Cirrus clouds are high-altitude thin clouds composed of ice crystals with a wispy fibrous appearance. They are classified as high-level clouds (above FL230 in temperate regions) and are the defining member of the cirrus cloud family.

Medium layered clouds → INCORRECT. Medium layered clouds belong to the alto- family (altostratus, altocumulus), found between approximately 6500 and 23000 ft. These are distinct from the cirrus family both in altitude and composition (water droplets rather than ice crystals at lower levels).

Low puffy clouds → INCORRECT. Low puffy clouds describe cumulus or stratocumulus clouds at low altitude. Cumulus clouds are convective in origin and form at low levels in unstable air. They are structurally and compositionally different from the thin fibrous high-altitude cirrus.

Thick rain-producing clouds → INCORRECT. Thick rain-producing clouds are nimbostratus (producing continuous rain from a warm front) or cumulonimbus (producing heavy showers and thunderstorms). Both are deep clouds associated with significant precipitation, entirely unlike the thin non-precipitating cirrus.