The correct answer is A. 1.
A pyrenoid is a small, proteinaceous structure found in the chloroplasts of some algae and cyanobacteria. It is the site of starch synthesis and is surrounded by starch grains. Pyrenoids are typically spherical or ovoid in shape and range in size from 1 to 10 μm.
Chlamydomonas is a unicellular green alga that is found in freshwater habitats. It has a single chloroplast that contains a pyrenoid. The pyrenoid is responsible for the synthesis of starch, which is used as a food reserve by the cell.
The other options are incorrect because they do not represent the number of pyrenoids that are found in Chlamydomonas. Option B, 2, is incorrect because Chlamydomonas typically has only one pyrenoid. Option C, 3, is incorrect because Chlamydomonas has never been observed to have three pyrenoids. Option D, 4, is incorrect because Chlamydomonas has never been observed to have four pyrenoids.