Which of the Following Features Distinguishes a System from a Heap-I.e

Which of the following features distinguishes a system from a heap-i.e., a collection of parts?

A) A system changes if you take away or add pieces; if you cut a system in half, you do not get two smaller systems, but rather, you get a system that will not function. A heap can be divided into pieces, each of which can function on its own.
B) In a system, the arrangement of the pieces is crucial because the parts are connected to each other and work together; in a heap, the arrangement is irrelevant.
C) The behavior of a system depends on its overall structure, while in a heap, size, rather than structure, determines behavior.
D) All of these are correct.