Dance critic from Europe: The improved quality of ballet in the United States is the result of more Europeans' teaching ballet in the United States than ever before. I know the proportion of teachers who were born and trained in Europe has gone up among ballet teachers in the United States, because last year, on my trip to New York, more of the ballet teachers I met were from Europe-born and trained there -than ever before.
Which of the following identifies a questionable assumption made by the dance critic's reasoning?
(A) The argument overlooks the possibility that some ballet teachers in the United States could have been born in Europe but trained in the United States.
(B) The argument assumes that the ballet teachers whom the critic met last year on the critic's trip to New York were a generally typical group of such teachers.
(C) The argument assumes that the teaching of ballet in the United States is superior to the teaching of ballet in Europe
(D) Other possible reasons for the improved mental attitudes of United States dancers are not examined.
(E) The argument assumes that dancers born and trained in Europe are typically more talented than dancers born and trained in the United States.