For London, I used the flag of the City of London, which has a population of less than 10,000, rather than the flag of Greater London (which looks like this), because the latter is a strictly a county. The answer is shown as 'City of London' to reflect this. I also chose this flag because I believe London is easier to guess based on this flag than the Greater London flag.
The New one is: https://en.wikipedia.org/wiki/Kinshasa#/media/File:Flag_of_Kinshasa,_DRC.svg
Please update your quiz!