The answer is c hope i helped
I believe the answer is Rhodophyta.
Classification of protists in one kingdom is difficult because protists more closely resmble members of other eukaryotic kingdoms than they do other protists. Rhodophyta orred algae are distinct eukaryotic lineage characterized by the accessory photosynthetic pigments phycoerythrin, phycocyanin and allophycocyanins arranged in phycobiliomes and the absene of flagella and centrioles.
The walls surrounding the coral are called “theca”
