The correct option is B CSO
For estimation of National Income, the government established Central Statistical Organisation (CSO) which regularly publishes national income data.
The government is planning to merge Central Statistical Organisation (CSO) and National Sample Survey Organisation (NSSO) for promoting statistical network in the country. The newly merged unit will be named as National Statistical Organisation (NSO). The head of the organisation will be designated as Chief of Statistician of India and will be having the rank of 'Chief Secretary'.