How did advocates of expansionism react to Turner's frontier thesis? (3 points) a They argued Americans should move from rural areas to expand the nation's new frontier—the cities. b They argued Congress should enact new protections for America's natural resources to rebuild the frontier. c They argued Americans should seek new lands overseas as a "safety valve" to help release popular discontent. d They argued Americans should turn away from the culture of the American West and embrace European culture.

c They argued Americans should seek new lands overseas as a "safety valve" to help release popular discontent.

Explanation:

Frederick J. Turner, who was widely known for his work, The Frontier Thesis, suggested the followings:

1. That, frontier acted as "safety valve" which reduce the overpopulation of the Americans, as it gives the Americans, a ready made land to access and take over.

2. It also suggested that, the frontier gave opportunities to the Americans both in economically and geographically.

3. It is also suggested that, fronteir led to civilization of the underdeveloped society and their colonization.

Hence, considering the available options, the advocates of expansionism react to Turner's frontier thesis, by arguing that, Americans should seek new lands overseas as a "safety valve" to help release popular discontent.

the answer to this question is the third option. hope this