Unicellular algae surrounded by thick plates of armor

The dinoflagellates are a characterization subgroup of green growth. They are an expansive gathering of whip eukaryotes that establish the phylum Dinoflagellata. Most are marine microscopic fish, yet they likewise are regular in freshwater territories. Their populaces are dispersed relying upon ocean surface temperature, saltiness, or profundity.  

The dinoflagellates (Greek δῖνος dinos "spinning" and Latin flagellum "whip, scourge") are a characterization subgroup of green growth. They are an extensive gathering of lash eukaryotes that comprise the phylum Dinoflagellata. Most are marine tiny fish, yet they additionally are basic in freshwater territories.

d is the right answer