Explanation:

- Section 84: Deals with when a foreign State may sue in the Code of Civil Procedure. It sets the provisions under which a foreign state can be recognized to file a lawsuit.

- Section 88: Typically relates to appeals in different laws; not about foreign states suing in CPC (Code of Civil Procedure).

- Section 90: Covers special case suits, but not specifically the situation for foreign states.

- Section 92: Often pertains to public charities and trust-related suits rather than foreign state issues.

Answer: Section 84