Three of the Following Teachers Are Using "Scaffolding" to Help

Three of the following teachers are using "scaffolding" to help their students learn. Which one is not necessarily providing scaffolding?

A) Ms. Applegate gives her students the structure she'd like them to follow when they write their first essay.
B) Mr. Bernardo teaches the backhand tennis swing by gently guiding each student through the correct movement a few times.
C) Ms. Chen gives her class some hints about how to solve an especially difficult word problem.
D) Mr. Donaldson takes his students on a field trip to the art museum so they can learn more about the different types of art.