Explanation:
Russian- born George Balanchine influenced the development of American ballet the most. Balanchine rose to world prominence on the strength of his stripped-down, deeply musical works. His ballets stripped dancers of their tutus and frills and allowed them to perform in the lean simplicity of rehearsal clothes. Balanchine’s love for dance originated after training at the city's Imperial Ballet Academy, the starting ground for many dancers from the country's legendary Kirov Ballet. By the age of 30,he co-founded the School of American Ballet and eventually the New YorkCity Ballet.
That would be two sopranoes and one bass. So the answer is B
I am pretty sure it is called a cultural trade
