Which of the following is Chlamydomonas?
This is Chlamydomonas, a form of algae. They are usually colony dwellers. They are found in stagnant water and on damp soil, in freshwater, seawater, and even in snow as "snow algae".
This is an irregularly shaped protozoan called Amoeba.
This is a fungus of the genus Aspergillus.
This is a fungus of the genus Penicillium.