With Which of the Following Statements Does the Overlapping-Waves Approach

With which of the following statements does the overlapping-waves approach agree?

A) At any given time, children possess several different strategies for solving a particular problem.
B) Children cycle through strategies regardless of whether or not they are effective.
C) Children of a given age use a particular strategy to solve a particular class of problems.
D) With development, children add strategies to their repertoire without removing older strategies.
E) Children's strategic variability accounts for their poor problem solving.