Shakespeare's plays often contain puns, which are

a. archaic phrases
b. slang terms
c. plays on words
d. rhyming lines

(this is under the poetry subject but they didn't have a poetry subject)

Shakespeare's plays often contain puns, which are

C. Plays on words.

the word that best matches the meaning of the expression "went to the big ocean" is died.

the goldfish died, which is why the father looks at the children mournfully. the "big ocean" is the father's way of saying fish heaven. he could have just said that the goldfish died, but this way, the children imagine the fish in a bigger, better place instead of just picturing a dead fish.

explanation:

a low four-wheeled open carriage of a kind formerly used in russia.