In Which of the Following Situations Is a Teacher Demonstrating

In which of the following situations is a teacher demonstrating skill at handling what Kounin calls overlapping?

A) A teacher deals with students of different ages on a playground by taking their various ages into account.
B) A teacher gives the class a free period and uses the time to help several students who have fallen behind.
C) A teacher notices that two students are sleeping, stops the lesson, wakes the students, and then begins again.
D) A teacher working with one group of students turns momentarily to tell another group to get busy, then quickly redirects his attention to the first group.