Which of the Following Is a Parasitic Relationship

Which of the following is a parasitic relationship?

A) The Dutch elm disease fungus infects and kills elm trees.
B) The yellow fever virus causes fever and sometimes kills humans.
C) A female tick fastens to the skin of a human host and draws blood for nutrition to make her eggs.
D) The trichina worm burrows into muscle tissue, forms a cyst, and waits to continue its cycle until a predator consumes the host.
E) All of the answer choices describe parasitic relationships.