According to Lev Vygotsky's Concept of the Zone of Proximal

According to Lev Vygotsky's concept of the zone of proximal development (ZPD) ,learning is:

A) achieved by discovering which answers will lead to rewards.
B) achieved by assimilating new understandings to accommodate the demands of the world.
C) affected by how the environment and genetically programmed learning ability interact during a critical period.
D) a social activity between a less knowledgeable child,and another adult or child who is more knowledgeable.