D
Columnist: Although much has been learned, we are still largely ignorant of the intricate interrelationships among species of living organisms. We should, ttherefore, try to preserve the maximum number of species if we have an interest in preserving any, since allowing species toward which we are indifferent to perish might undermine the viability of other species. Which one of the following principles, if valid, most helps to justify the columnist's argument?
A: We should always undertake the course of action that is likely to have the best consequences in the immediate future.
B: It is strongly in our interest to preserve certain plant and animal species.
C: We should not allow the number of species to diminish any further than is necessary for the flourishing of present and future human populations.
D: We should not allow a change to occur unless we are assured that that change will not jeopardize anything that is important to us.