Step 1: Understanding the Concept
The question requires placing four distinct historical events—three global pandemics and one Indian national policy—in the correct chronological order from earliest to latest.
Step 2: Identifying the Years of Occurrence
Let's determine the approximate year for each event:
(B) Spanish Flu: This was a deadly influenza pandemic that occurred from 1918 to 1920.
(D) First Population Policy in India: India was the first country in the world to launch a national programme for family planning. This policy was initiated in 1952.
(C) Asian Influenza: This was a global pandemic of influenza A virus subtype H2N2 that originated in Asia in 1957.
(A) Hong Kong Influenza: This was another global influenza pandemic caused by the H3N2 strain of the influenza A virus, which started in Hong Kong in 1968.
Step 3: Arranging in Chronological Order
Based on the years identified, the correct sequence is:
1. Spanish Flu (1918)
2. First Population Policy in India (1952)
3. Asian Influenza (1957)
4. Hong Kong Influenza (1968)
The sequence of the letters is (B), (D), (C), (A).
Step 4: Final Answer
The correct chronological order corresponds to option (1).