Primarily made with either beef or chicken the broth known as 'pho' is associated with which Asian country?

Phở or pho is a Vietnamese soup consisting of broth, rice noodles called bánh phở, a few herbs, and meat, primarily made with either beef or chicken. Pho is a popular street food in Vietnam and the specialty of a number of restaurant chains around the world. Pho originated in the early 20th century in northern Vietnam, and was popularized throughout the rest of the world by refugees after the Vietnam War. Because pho's origins are poorly documented, there is significant disagreement over the cultural influences that led to its development in Vietnam, as well as the etymology of the word itself. The Hanoi and Saigon styles of pho differ by noodle width, sweetness of broth, and choice of herbs.

In the aftermath of the Vietnam War, Vietnamese refugees brought pho to many countries. Restaurants specializing in pho appeared in numerous Asian enclaves and Little Saigons, such as in Paris and in major cities in the United States, Canada and Australia. In 1980, the first of hundreds of pho restaurants opened in the Little Saigon in Orange County, California.