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

Which of the following definitions best describes 'debris flow'?

A. the concept is a naturally occurring solid aggregate of minerals and/or mineraloids. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic. [Wikipedia]
B. A the concept is an individual foreign crystal included within an igneous body. Examples of xenocrysts are quartz crystals in a silica-deficient lava and diamonds within kimberlite diatremes. [Wikipedia]
C. A mixture of water-saturated rock debris that flows downslope under the force of gravity (also called lahar or mudflow).
D. A rapid and unusually sudden sliding or flowage of unsorted masses of rock and other material. As applied to the major avalanche involved in the eruption of Mount St. Helens, a rapid mass movement that included fragmented cold and hot volcanic rock, water, snow, glacier ice, trees, and some hot pyroclastic material. Most of the May 18, 1980 deposits in the upper valley of the North Fork Toutle River and in the vicinity of Spirit Lake are from the the concept.

Answer: A mixture of water-saturated rock debris that flows downslope under the force of gravity (also called lahar or mudflow).