Explanation:

- Option 1: IMF (International Monetary Fund)

- Focuses on global monetary cooperation.

- Works to secure financial stability and facilitate international trade.

- Provides resources to member countries in financial difficulty.

- Option 2: AIIB (Asian Infrastructure Investment Bank)

- Aims to improve economic and social development in Asia.

- Primarily finances infrastructure projects.

- Does not manage the broader international financial system.

- Option 3: FATF (Financial Action Task Force)

- Sets standards to combat money laundering and terrorist financing.

- Ensures the integrity of the international financial system by promoting policies.

- ?? Correct Answer: This is the body focused on financial system integrity.

- Option 4: ADB (Asian Development Bank)

- Focuses on economic development and projects in the Asia-Pacific region.

- Provides loans and technical assistance but not primarily for global financial system integrity.