which of these is an example of perfect democracy?

A, USA

B,UK

C.India

To strive for an ideal form of government is mere a utopia. No form of government or system is perfect, one can only work for better governance. We can only say that US is the oldest Democracy whereas India is the largest Democracy and UK as good example of Constitutional monarchy with a rule of law. They are good examples of a Democratic rule, but not perfect.

Democratic form of government has been questioned on various fronts that it leads to instability, it is about competition and power, gives importance to numbers, leads to delays in decision making process, even democracies track record with that of economic development has been questioned, but nevertheless democracy is the most preferred and better form of government than any any other forms for the very reason that it ensures people's participation guranteeing them basic rights that enhances their dignity. 

There are flaws  in the actual practice of democracy, but then the responsibility rests with citizens of the country who can make the government more accountable and answerable by being vigilant and alert.