Let us look at the step by step approach to this question.
The first step would be identify the Question type : From the word "Conclusion" given in the argument, we come to know that the question seeks an option that is supported by the information given in the argument. Hence this can be categorized as an Inference Question.
The obvious step to solve an Inference question would be to first check for the obviously wrong answers and eliminate them. This also means you can eliminate answer choices that are not always true.
A - Not true as per the information given as there is no relationship between Planktons and earth's temperature directly.
B - Very generic statement. There could be species that do not adapt at all.
C - This option tends to make us believe that sulphate particles are the only reason why clouds are formed - This is incorrect.
D - OA
E - This is just an example. Again, it may not be the planktons directly. It is planktons plus the other factors.
Hope that helped - All the best
Thanks,
Saikiran Dudyala
Byju's GMAT Expert