Hi @asad24, We'll start with a breakdown of the argument: Conclusion: Funds must be raised to preserve at least those exhibits that will be most valuable to science in the future
P1) exhibits currently decaying P2) without these exhibits we couldn't have found out important stuff about pesticides.
The question stem here "the argument presupposes that" is a strengthen with necessary premise type. Recall that for this question type we have the tool of the negation test. To perform the negation test we negate and answer option and if the negated version ruins the argument (i.e. makes the conclusion fall apart), then this option is correct. This is because when the negated version ruins the argument, the normal (i.e. non-negated) form must be presupposed in order for the argument to work - without it, the argument would fall apart.
Here if we negate answer option D, we can "it cannot be known at this time what data will be of most use to scientific investigators in the future". This ruins the argument because in this case how could we get to the conclusion that we need to preserve the most valuable ones. We wouldn't even know which ones are the most valuable. This makes D our correct answer.
