The correct answer is: a) Identify illegal immigrants.
The National Register of Citizens (NRC) is a register of Indian citizens. It was first prepared in 1951, and a new one was being prepared in Assam from 2013 to 2019. The NRC in Assam aimed to identify illegal immigrants from Bangladesh.
Option b) is incorrect because the NRC is not meant to update citizenship records. The NRC is a separate exercise from the process of updating citizenship records.
Option c) is incorrect because the NRC is not meant to resolve land disputes. The NRC is a register of citizens, and it does not have any bearing on land disputes.
Option d) is incorrect because the NRC is not meant to provide social welfare benefits. The NRC is a register of citizens, and it does not have any bearing on social welfare benefits.