Interesting, cos from a Brit perspective I'd say "whooped" if I meant (c) - as in yeeeeeeeeeeeehah. To the extent the whoop became more of an aaaooooowwwwl I'd say "howled".

Hooting is what owls do over here.

I'd probably get the USn meaning of "hooted" in context, mainly because if the writer meant (a) honked the horn[repeatedly, with a bit of rhythm and fun, to be more specific] I'd expect the word used to be "tooted". Or "honked" itself, of course, though left at that our hero would be a goose.

So on what side of the Pond did the phrase "It'll be a hoot" originate?