Geography, environment, and movement in Vietnam
(A) successfully fostered the growth of a uniform Vietnamese culture.
(B) have increasingly isolated Vietnam from its neighbors.
(C) divided the nation into two cultural divisions—one in the south along the Mekong River and the other in the north along the Red River.
(D) have made Chinese influence in Vietnam inevitable.
(E) led to the spread of Christianity and Islam throughout the country
Answer: C