Explanation:

- Option 1: Delegation of legislative authority by the Union legislature to the executive

- Correct. It refers to the executive creating detailed rules and regulations under the framework of an existing law passed by the legislature.

- Example: Rules under an Act created by a government ministry.

- Option 2: Delegation of legislative authority by the Union legislature to either the judiciary or the executive

- Incorrect. Delegation generally doesn't extend to the judiciary. It's typically between the legislature and the executive.

- Option 3: Delegation of legislative authority by the Union legislature to a State legislature on subjects under the Concurrent List

- Incorrect. Although the Concurrent List allows both Union and State legislatures to make laws, delegation isn't involved here between levels of government like this.

- Option 4: None of the above

- Incorrect. This doesn't describe delegated legislation correctly.

Correct Answer: Option 1