Explanation:

- Union Government: This option is incorrect. The union government does not declare lockouts in individual industries.

- State Government: This option is incorrect. Similar to the union government, the state government also does not declare lockouts in industries.

- Management: This is the correct option. A lockout is declared by the management of a company, often as a strategy to gain an advantageous position during labor disputes.

- Trade Union: This option is incorrect. Trade unions may initiate strikes, but they do not declare lockouts.