It can be inferred from the passage that Brian Swann believes which of the following about the European settlers of America？( )

A.They probably were more literate，on the average，than the general European population they left behind.
B.They probably thought it necessary to understand American Indian politics before studying American Indian literature.
C.They probably did not recognize evidence of an oral poetic tradition in the American Indian cultures they encountered.
D.They probably could not appreciate American Indian poetry because it was composed in long narrative cycles.