Correct Answer: i-b, ii-a, iii-d, iv-c

Solution : The correct option is i-b, ii-a, iii-d, iv-c .

Chlorophyceae (Green Algae): Contains chlorophyll a and b, can be unicellular or multicellular, and is found in freshwater and marine environments.

Phaeophyceae (Brown Algae): large, multicellular seaweeds with brown colour due to fucoxanthin and chlorophyll a.

Rhodophyceae (Red Algae): multicellular, red or purplish colour due to pigments like chlorophyll a, phycocyanin, and phycoerythrin.

Cyanophyceae (Blue-Green Algae): prokaryotic (cyanobacteria), unicellular or filamentous, capable of nitrogen fixation.