Dinoflagellates are :A) a group of algae with cell walls made of plates of cellulose and with two groves in the cell wall.B) a group of shelled amoeba with porous shells composed of calcium carbonate. C) A group on microalgae with a cell wall that is made up of two overlapping halves. D) membwrs of the Rhodophyta E) Macroalgae, seaweed, that are mostly marine, multicellular, the largest of all protist and are most common in cold coastal waters.