Which of the following groups of algae produces algin?

Step-by-step solution

Alginic acid (or algin or alginate) is an anionic polysaccharide distributed widely in the cell walls of many brown algae (Phaeophyceae). It is a phycocolloid which is obtained commercially from Laminaria, Macrocystis, Nereocystis, Fucus, Sargassum etc.