Which of the following statements is correct in the context of golden algae?

A) Have a coenocytic mycelium
B) Are mostly unicellular, with shells containing silica
C) Are multicellular stramenopiles that are ecologically important in cooler ocean waters
D) Are mostly unicellular, biflagellate freshwater and marine stramenopiles
E) Are excavates with one or two nuclei and no functional mitochondria