What Does Scaffolding Mean in Constructivist Teaching

What does scaffolding mean in constructivist teaching?

A) Doing tasks for children when they are too hard for them.
B) Giving children challenging tasks and letting them work independently to solve them.
C) Separating children to avoid conflicts in the classroom.
D) The dynamic and active assistance from the more expert partner, relying heavily on verbal cues, prompts, modeling, and questions.