I think It would be B because in sounds like the best one in my opinion sorry if I am wrong
Use iodine.
Iodine solution makes the sample you want to study of microscopic organism more visible.
Biodiversity researches summarize the most important direct cause of extinction resulting from human activities using the acronym HIPPCO: Habitat destruction, degradation and fragmentation; Invasive (nonnative species); Population growth and increasing use of resources; Pollution; Climate change, and Overexploitation.