A scientist used a light microscope to view an algal cells because light microscope is able to magnify objects up to about a thousand times. Various cellular organelles, such as nuclei, chloroplasts, and mitochondria etc can also be seen clearly with the help of light microscope so that's why scientist used light microscope to study algal cells.
C is the correct answer i think, because scientist do not consider them as living since they lack the properties that all living organisms have or should have