Correct Answer: Rhodophyceae

Solution : The correct answer is Rhodophyceae .

Red algae, scientifically known as Rhodophyta, are among the earliest eukaryotic algae, boasting a rich evolutionary history. This extensive group encompasses over 7,000 recognised species, with ongoing taxonomic revisions. The characteristic red colour of these algae is attributed to pigments like phycoerythrin and phycocyanin, masking other pigments such as chlorophyll a (absence of chlorophyll b), beta-carotene, and distinctive xanthophylls.