The author's attitude towards westward expansion is ______.

A．will be smaller than a fw years ago
B．will not be as small as people expect
C．will prove to be a threat to the world
D．will not consitute as serious a problem as expected

A．It is altruistic.
B．Americans believed that they should bring freedom and democracy to the unfortunate people.
C．It reflects American's deep-rooted racism.
D．Amercans believed that their system would do benefits to others.