What is the difference between joke and fun?

[Dasha]

Test No. incompl/inter-8 "Going on foot", question 2

Who said growing up was .........?

(a) fun
(b) joke
(c) humour
(d) laughter

Test No. incompl/inter-8 "Going on foot", answer 2

Who said growing up was fun?

Correct answer: (a) fun

Your answer was: incorrect
Who said growing up was joke?
_________________________

Hi Alan! Why word joke doesn't fit in here?

[Alan]

It would have to be a joke.
_________________
English as a Second Language
You can read my ESL story Saying It Twice