A Common Problem Associated with Peer Learning and Whole Class

A common problem associated with peer learning and whole class discussions is that

A) scaffolding is not effective in these formats.
B) children's explanations are too long and detailed.
C) teachers in North America prefer peer learning and whole class discussions over a teacher-lecturer format.
D) teachers in North America may be reluctant to use these approaches, because they are afraid that students may not be able to generate the correct answer if these approaches are used.