"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 <u>opinion</u>:
appreciation verbs like <em>enjoy</em>, <em>hate</em>, <em>wish</em>, <em>believe, </em>etc.
adjectives expressing value judgement like <em>best</em>, <em>good</em>, <em>bad</em>, <em>favorite</em>, <em>disappointing</em>, <em>fascinating</em>, <em>boring</em>, etc.
clear involvement of the narrator, for example when the subject is <em>I</em> or <em>we</em>.
Conversely, a <u>factual</u> 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."
