Task: Class Definition Understanding (ontology: Earth_Environment/SWEET)

Which of the following definitions best describes 'altostratus'?

A. Water droplets suspended in the atmosphere in the vicinity the earth's surface that affect visibility.
B. A violent east wind on Lake Tanganyika in Africa.
C. A principal cloud type (cloud genus) in the form of a gray or bluish (never white) sheet or layer of striated, fibrous, or uniform appearance.
D. A local dry wind in the northern plains of Java, resembling the foehn. It is caused by a wind crossing the mountains near the south coast and pushing between the volcanoes.

Answer: A principal cloud type (cloud genus) in the form of a gray or bluish (never white) sheet or layer of striated, fibrous, or uniform appearance.