Explanation:

- Option 1: By will

- A will is a legal document expressing the wishes of how a person wants their property distributed after their death. It is not covered by the Transfer of Property Act, as this act only concerns with transfers between living persons.

- Option 2: By Parties

- This type of transfer involves transactions between individuals or entities. The Transfer of Property Act governs these interactions.

- Option 3: By operation of law

- Transfers occurring due to legal requirements or judicial decisions fall under this category. Such transfers are not covered by the Transfer of Property Act.

- Option 4: None of above

- Incorrect, as not all given options are covered by the Transfer of Property Act.

Answer: Option 3 - By operation of law