Arrange the following events of Cold War era in the chronological order and choose the correct option -
A. Berlin Blockade
B. Harry Truman's announcement of the Truman Doctrine
C. Ho-Chi-Minh proclaims the independence of Democratic Republic of Vietnam
D. Formation of NATO
1
B, A, C and D
2
A, B, C and D
3
C, B, A and D
4
B, C, D and A