I know ... hot dog

[Nefertiti]

1. I know what's a hot dog.
2. I know hot dog.
3. I know what a hot dog is.
4. I know what hot dog is.
5. Any better suggestions

Pick the appropriate answer(s) and please explain.

Thanks

[Khalid79]

Hi dear , ( im not a teacher ) .

I think the correct statement is (4 ) after you add the article ( the ) infron of hot dog.
the subject here ( hot dog) should be placed immediately after what and before the auxiliary verb is .

[cyber_man]

I agree with Khalid79. In may opinion you should use these forms :
Number 4 (add 'the' article before hot dog)
or
I know what hot dogs are.

[Anglika]

Personally I would go for #3 since this is a general comment about hot dogs.