Step 1: Understand the bodies involved.
The Central Statistical Office (CSO) handled national income and GDP work. The National Sample Survey Office (NSSO) ran big surveys on jobs, spending and living conditions.
Step 2: Why merge them.
Having two separate bodies caused overlap. The government wanted one strong, single statistical agency.
Step 3: The merger.
CSO and NSSO were merged into the National Statistical Office (NSO) under the Ministry of Statistics.
Step 4: The year.
This merger was officially announced in 2019.
Step 5: Conclude.
So the correct year is 2019.
Answer: 2019