What is the source of Agar Agar

Answer: Option D

Algae is the source of Agar Agar.
Agar or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae.
Agar was first subjected to chemical analysis in 1859 by the French chemist Anselme Payen, who had obtained agar from the marine algae Gelidium corneum.
It forms the supporting structure in the cell walls of certain species of algae and is released on boiling. These algae are known as agarophytes, belonging to the Rhodophyta (red algae) phylum.