Which sentence develops the main idea and should be placed after sentence 5?

No matter what Mrs. Crimston did, the kids seemed restless.
A
They sat in their seats, and they fantasized about what they were going to do during their summer vacations.
B
They worried about whether or not they were going to make it to the end of the year when they could begin their summer vacation.
C
They talked and yelled to each other, fidgeted in their seats, and didn't pay attention to Mrs. Crimston or the class rules.
D
They got very quiet and started coloring in their books while they daydreamed and wished for the school year to finally end.