When nations try to maintain the balance of power they A -promote equality among social classes B -try to prevent domination by one country
C - try to reduce their armies
D - promote peace among nations

b) try to prevent domination by one country

Explanation:

president thomas jefferson commissioned the expedition shortly after the louisiana purchase in 1803 to explore and to map the newly acquired territory, to find a practical route across the western half of the continent, and to establish an american presence in this territory before britain and other european powers

bless you your highness