What exactly are you trying to ask ?
1. had, would have went
2. liked, would have invited
3. did not protect, would have extinct
4. will be, did not
5. helped, would be
6. would have traveled, bought
7. should go, does not feel
8. would have traveled, had saved
The answer would be west coast
Could you provide more information on the question, so someone could answer it
The budget report for last year was very well researched.
You are looking for an adverb: a word to describe the adjective "researched".
"well" is the only adverb on the list. The other three are adjectives, which cannot describe other adjectives.