Yeah, this one uses the largest ones in each country. A good website to use for finding number of places with a city name is https://iafisher.com/projects/cities. Using this you can find all the places in the world with a specific name. You can also do a lot of other stuff with that website, I like to use it for a map of all the cities ive ever visited.
https://www.jetpunk.com/user-quizzes/1520455/countries-with-a-city-called-georgetown
Additionally, there are 11 cities called "San Jose" in the Philippines, and 10 in Mexico. I assume this quiz uses the largest one.