Which Teacher Is Using Vygotsky's Concept of Scaffolding in Teaching

Which teacher is using Vygotsky's concept of scaffolding in teaching math?

A) Mr. Chen, who makes sure his students have mastered each step in learning long division, and then gradually backs off and allows the class to practice on their own
B) Mr. Shepherd, who drills his students in long division, and then gives a multiple-choice test to see what the class has learned
C) Mr. Olinksy, who tries to get his students to figure out long division on their own
D) Ms. Lahod, who goes over long division in a single class period