Answer:
D) The distance between a person’s current developmental level and their potential development level with assistance from a more capable ally
Explanation:
This concept was given by a Soviet psychologist named Lev Vygotsky. A child always followed elders in family and develop the ability to do a task without any help. It is the distance between actual development indicated by independent problem solving and potential development under the guidance of capable peers. Now it has been modified, expanded and changed in new concepts. Scaffolding is another concept that is closely related to ZPD concepts. Thus proximal is referred to as those skills which are close to the learner and can mastery over them.