The usual course of events when nature comes unhinged—as i

OPTION A:- INCORRECT
And the address the damage done and they in the last clause creates parallelism error.
You cannot say "the researchers look,try and they access."

OPTION B:- INCORRECT
What happened, assessing and addressing the damage done---again parallelism error in the last cause. "that researchers look, try, assessing ......." is not a parallel series.

OPTION C:- INCORRECT
Back in the time, try to understand what happened, assess and address the damage done- the series lack a conjunction before the last element. The last two verbs go together and should really be thought of as one.

OPTION D:- INCORRECT
For researchers and official to officials to look back in the time, try to understand what happened, as they recess and address the damage done - here there should have been "AND"between clause 1 and clause 2 ..to look back and try to understand.

OPTION E:- CORRECT
Trying -verb-ing form correctly modifies the previous clause and totally avoiding the parallel structure.Links the element correctly, although the method is confusing to students. Also, the primary sentence is simply "the usual course is for researchers to look back in time...., as they assess and address the damage
As you can see in this problem, using slash-and-burn to assess core elements is essential i many confusing sentence construction problems- without it, you may not notice what makes many of the series in this problem incorrect.