Which of the following documents need to be compulsory registered?

Section 18 of Registration Act 1908 provides for optional registration of some documents such as: 1. Instruments which purport to create, assign, declare, limit or extinguish, whether in present or in future, any right, title or interest in any immovable property of value less   than Rs 100. 2. Instruments acknowledging the receipt or payment of any consideration on account of the creation, declaration, assignment, limitation or extinction of any such right, title or interest 3. Will 4. Lease of immovable property not exceeding 1 year 5. Decree or order of court comprising an immovable property valued below Rs. 100 6. Instruments which purport to create, assign, declare, limit or extinguish, any right, title or interest in any movable property