The correct option is
D Both B and C
A) Antedon does not eat small animals. It eats microscopic animals such as plankton.
B) Antedon (Sea lily) eats plankton and waste. Plankton is microscopic plants and animals that drift in the water.
C) Antedon also feeds on detritus. Detritus is dead particulate organic material. It includes the bodies or fragments of dead organisms as well as faecal material.
D) Antedon feeds on plankton and detritus.
So the correct answer is 'Both B and C'.