The correct option is A that have phycoerythrin pigment
Commercially used carrageenan comes from Chondrus, which is a red alga.
Phycoerythrin, the pigment for red colour, is a characteristic of all red algae.
Pyrenoids are storage bodies in the chloroplasts of green algae.
Mannitol is the stored form of food in brown algae. Fucoxanthin is the pigment responsible for their brown colour.