Refer to the Figure

Refer to the figure. Which statement about the eukaryotes shown is true?

A) They are specialized to withstand pounding by surf.
B) Their color results from a symbiotic relationship with dinoflagellates.
C) Their fossilized remains make a major contribution to limestone.
D) Their fronds are stiffened with silica.
E) Their primary habitat is above the tidal zone on the seashore.