The correct answer is (a) Chlamydomonas snowae.
Chlamydomonas snowae is a species of green algae that is found in snow and ice. It is the most common cause of red snow, which is caused by the algae’s red pigments. The algae reproduces in the spring and summer, when the snow melts. The spores are then carried by the wind to new areas, where they can start new colonies.
Chlamydomonas snowae is not harmful to humans, but it can be a nuisance. The algae can make snow slippery and difficult to walk on. It can also stain clothing and other surfaces.
(b) Chlamydomonas nivalis is a species of green algae that is also found in snow and ice. However, it is not as common as Chlamydomonas snowae and does not usually cause red snow.
(c) Both (a) and (b) is not the correct answer because Chlamydomonas snowae is the most common cause of red snow, while Chlamydomonas nivalis is not as common and does not usually cause red snow.
(d) None of these is not the correct answer because Chlamydomonas snowae is the most common cause of red snow.