A: Meyrin, Genève, Switzerland
In March 1991 Tim Berners-Lee released the first web browser, WorldWideWeb, to a number of people at CERN. This release introduced the web to the high energy physics community, and began the spread of the World Wide Web.
Berners-Lee provided an explanation of how he created the browser and some screenshots of versions from 1993 on his website at this link: https://www.w3.org/People/Berners-Lee/WorldWideWeb.html