With reference to the Supreme Court’s decision in the Mandal case of 1992, consider the following statements:

1. The Court upheld the constitutional validity of 27 per cent reservation for Other Backward Classes.
2. It directed that the advanced sections among Other Backward Classes should be excluded from reservation.
3. It recognised reservation in promotions as a generally permissible feature of Article 16(4).
4. It held that total reservation should ordinarily not exceed 50 per cent, though extraordinary circumstances may justify an exception.

Which of the statements given above are correct?