With reference to the constitutional provisions governing the classification of Other Backward Classes, consider the following statements.
- The National Commission for Backward Classes (NCBC) is a constitutional body.
- The NCBC has the power to directly add or remove communities from the Central OBC List.
- Under Article 342A, the Central List of socially and economically backward classes can be altered only by a law of Parliament.
- States have no authority to prepare their own lists of OBCs for State purposes.
How many of the above statements are correct?