Sharon, 3, can solve 4-piece jigsaw puzzles on her own, but needs her parents' help to solve 6-piece jigsaw puzzles. Which of the following represents the upper limit of Sharon's zone of proximal development (ZPD) for solving such puzzles?
A. Sharon moving on to 10-piece puzzles
B. Sharon solving a 6-piece puzzle on her own
C. Sharon helping her 2-year old brother with 4-piece puzzles
D. Sharon mastering 4-piece puzzles

B. Sharon solving a 6-piece puzzle on her own

Explanation:

As originated by Lev Givotsky(1896-1934), the zone of proximal development, abbreviated as ZPD (zona blizhaishego razvitiia, in original Russian), refers to the zone that is most closest and most immediate to the psychological development of the child including a range of emotional, cognitive, and psychological processes. It is also described in educational research of today as the difference between what a learner can do without help, and what they can do with assistance from a knowledgeable adult.