I would say B. To give a sense of both coninuitly and change over time.
Because:
Cronological order is the order in which somthing happens, and this is the best option that work with that idea.
A is wrong. Because how I read it it seams that it is saying bad things only happen once, and we know that is not true.
C is wrong because some things do change a LOT over time, and dosn't make much since.
D is wrong because all events are important in some way, and that would be "Order of Importance"
