Answer:
(A). Commerce and industry would decline as the nation expanded its agricultural base.
Step-by-step explanation:
"Manifest destiny" (coined by John Sullivan in 1845) is an idea that God has destined the United States to expand its territories and dominate the whole North American continent from the Atlantic to the Pacific.
Expansion of territory led to availability of more lands for farming and as such, agricultural expansion and increase in food supply. It also brought about an increase in commerce and industry.