Explanation:

- Under the Transfer of Property Act (T.P. Act), a condition that absolutely restrains the alienation of property is generally not allowed.

- Option 1 - Valid: This would mean that a complete restriction on transferring property is acceptable, which is usually incorrect under the T.P. Act.

- Option 2 - Void: Generally, clauses that completely prevent the transfer of property are considered void because they go against public policy promoting free transferability.

- Option 3 - Voidable: This implies the condition is initially valid but can be nullified, which doesn't apply to absolute restraints.

- Option 4 - Irregular: This is not a typical legal term related to the T.P. Act.