[A] It refers to the phenomenon where the value or utility of a product or service increases as more people use it.

[B] It occurs when the cost per unit of production decreases as the scale of production increases.

[C] It suggests that a small change in one part of a system can have far-reaching consequences.

[D] It states that, after a certain point, the addition of one more unit of input (like labor or capital) while keeping other inputs constant, will result in smaller increases in output.