Which Statement Is a Correct Description of a Diffusion Chain

Which statement is a correct description of a diffusion chain?

A) A child learns that Behaviors A, B, and C are required to be performed in exact order to obtain reinforcement.
B) Responses learned by observation tend to be weak links in a behavior chain relative to responses acquired through reinforcement.
C) A child learns to perform a skill via operant conditioning and can then teach the skill to another child.
D) A child who learns a skill by observation can then serve as a model for another child to learn the skill via observation.