A factor in the U.S. government abandonment of the policy of one large

A factor in the U.S. government abandonment of the policy of one large reservation after 1851 was __________.

a. to enable wagon trains needed to cross the Great Plains without hindrances
b. a push by Southerners to allow slavery in the western territories
c. that Indians had traditional rivalries and needed to be kept apart
d. a desire to foster traditional Native American culture
e. the difficulty in finding large enough tracts of unsettled land

ANSWER
A