I think it's C. Because the rest just don't seem right to me.
A) To create a customs union for nations in the Americas aimed at improving economic relations.
Well in the case of the Mongols for example, being nomadic meant that their armies were highly mobile and adaptable. Conquests and long distance travel to conquer a civilization wasn't as difficult because it suited their nomadic lifestyle. They often adapted certain military technologies from the civilizations they conquered as well.
Answer:
a set of domestic programs in the United States launched by Democratic President Lyndon B. Johnson in 1964–65.
Explanation:
