You have to a citizen of the country you represent.
If you have Dual Citizenship, you can choose which country you want to represent. In this case, most athletes represent the country that is weaker in their sport, so they have a better chance of making it.
They have to represent the country.
burma
Japan
U.s.s.r
What country does Shaun White represent?
Jamaica
A NOC is a National Olympic Committee. Basically what they do is they represent a country, and it is up to them to decide which athletes participate in the Olympic games from the country. They also nominate their cities for candidates for future Olympic game venues.
South Korea
If you have the citizenship of the country you want to represent, ask them for try outs and if they accept you, you can represent them instead of Canada.
Sit on the toilet all day
Greece ... he was the winner of the marathon.
The country asks for it, they say why they want it in their country, and then a group of people decide by looking at the pros and cons of having the games there.