The Following Questions Refer to the Description Below

The following questions refer to the description below.
Terry catches a ray-finned fish from the ocean and notices that, attached to its flank, there is an equally long, snakelike organism. The attached organism has no external segmentation, no scales, a round mouth surrounded by a sucker and two small eyes. Terry thinks it might be a marine leech, a hagfish, or a lamprey.
-The snakelike organism turned out to be a hagfish. Consequently, why should Terry throw the fish he caught overboard, rather than having it for dinner?

A) It has mucus on its skin.
B) If it had an ectoparasite, then it must also have endoparasites.
C) The bite of the hagfish introduces paralytic neurotoxins, which Terry wants to avoid.
D) It was already sick or dying; otherwise, the hagfish would probably not have attacked it.