Which Statement About Observational Learning Is True

Which statement about observational learning is true?

A) The transmission of a novel behavior via a diffusion chain of observational learning has been documented across over a hundred children.
B) Learning a skill via observation only is effective if the learner also has the opportunity to practice the skill.
C) Preschool children can learn a skill via observation and then can successfully model this skill to other preschool children.
D) Reinforcement is necessary for observational learning to occur.