Paraphrase for 'eventually'

Hi teachers,
Eventually, two boys in another boat towed their boat back to the island.
Would the following paraphrases be appropriate for 'eventually' in the above sentence?
a) at some later time
b) at an unspecified future time; at an indefinite time in the future
c) after an unspecified period of time or an especially long delay
d) At some point in time

If 'b' is also appropriate. I'd prefer this one.
If 'eventually' implies some sort of delay then 'c' is the one. Right?

Thanks in advance.