Which is the correct flag?? 

I would just like to know what everyone or anyone has to say on this topic.  I have seen many different flags (flag icons) used for Cung Le under different situations.  An example of a time when a flag was used for Cung Le is in the page Strikeforce Current Champions, the flag is next to his name under the current champions section.  There has been many arguments on which flag is appropriate, the flags that have been used are; 
 The United States Flag, 
 The Vietnam Flag, and finally 
 The Flag of South Vietnam.  

If anyone can provide any input on the subject, it would be much appreciated. 67.163.17.113