Which word is the antecedent of the underlined pronoun?

the jellyfish propelled its body by filling with seawater and then pumping it back out.

a. jellyfish
b. seawater
c. body
d. pumping
it is underlined.

i think the best answer would be d allowing 30 seconds between response would give time for what was already said to sink down in your mind.

for me this my answer o fortunately, they did not notice, and i could pretend not to care.​   i hope this you