Which of the Following Scenarios Is the Best Example of Within-Class

Which of the following scenarios is the best example of within-class ability grouping?

A) Students from one class divide into three small groups for reading.
B) Students from the entire fourth grade are reshuffled into different classrooms for math.
C) Students from the entire third grade are combined into one class for physical education.
D) All students in the elementary school have lunch at the same time.