The study is based on EU Commission report 2015, including EU capitals' ranking according to 28 categories. Took five best capital cities of each category, and gave 5 points to category's best, 4 to the second best, etc.. Take a look what happened!
One of the capitals is slightly outside highlighted area of the map.
Also, Berlin would definitely be in this list.
True, the UK is no longer in the EU. However, the quiz reflects situation in 2015. Pls see the intro. It would be about time for me (or someone) to renew the quiz:))