(A) proposed the US reject all colonial territories.
(B) discussed the importance of naval bases in the Pacific to support expansion.
(C) proposed the Philippines be granted independence.
(D) ** discussed the need for unsettled land for economic and social development.
EXPLANATIONS BELOW
Concept note-1: -The Frontier thesis was formulated 1893, when American historian Frederick Jackson Turner theorized that the availability of unsettled land throughout much of American history was the most important factor determining national development.
Concept note-2: -Frederick Jackson Turner (November 14, 1861 – March 14, 1932) was an American historian during the early 20th century, based at the University of Wisconsin until 1910, and then Harvard University. He was known primarily for his frontier thesis. He trained many PhDs who became well-known historians.
Concept note-3: -Which of the following did Frederick Jackson Turner argue in his “frontier thesis"? American culture and identity developed from the ways in which the frontier shaped those who lived on it.