Explanation
The Palmella stage in Chlamydomonas is produced during unfavourable conditions.
During unfavourable conditions such as nutrient depletion, high population density, or adverse environmental conditions like high salinity or temperature, Chlamydomonas cells stop their motility and undergo mitosis repeatedly without undergoing cytokinesis, resulting in the formation of clusters of non-motile cells called palmelloids or the Palmella stage. This allows the cells to survive harsh environmental conditions until conditions become favourable again.
Therefore, the answer is B) During Unfavourable Conditions.
