"Glaciers Have No Defined Cleavage Planes, but Instead Flow Plastically

"Glaciers have no defined cleavage planes, but instead flow plastically." Evaluate this statement.

A) This statement is true, but it only applies to the upper part of a glacier.
B) This statement is false. Ice has cleavage similar to the mineral mica, and ice behaves like mica would under the same pressure.
C) This statement is partially true. The flow of glaciers is very slow and more similar to gravel than to plastic.
D) This statement is false. Glaciers do flow plastically, but also have well-defined cleavage planes similar to mica.