"Café Olympia serves coffee from all over the world" (B) states a fact rather than an opinion.
When writing essays for school, or researching information to support your writing, it is important to be able to stay factual and avoid stating opinions (unless you are specifically asked to do it, or unless you explicitly mention that you are quoting a biased work).
These characteristics should help you identify an opinion:
- appreciation verbs like enjoy, hate, wish, believe, etc.
- adjectives expressing value judgement like best, good, bad, favorite, disappointing, fascinating, boring, etc.
- clear involvement of the narrator, for example when the subject is I or we.
Conversely, a factual statement usually has:
- a distanced narrator, who does not get involved
- information which can be checked, like in answer B: "coffee from all over the world."