In MILITARY AND PARAMILITARY ACTIVITIES IN AND AGAINST NICARAGUA (Nicaragua v. USA), 1986 ICJ Rep 14, the ICJ held that:

1. In Nicaragua v. USA (1986), the ICJ found that the USA had: (i) violated the customary law obligation NOT TO USE FORCE (by mining Nicaraguan ports and other direct attacks); (ii) violated the customary obligation NOT TO INTERVENE in the affairs of another State (by supporting the Contras); (iii) violated the customary obligation TO RESPECT THE SOVEREIGNTY OF OTHER STATES; (iv) the USA was not entitled to invoke collective self-defence (since Nicaragua had not been attacked by El Salvador). 2. The judgment is foundational on use of force, attribution, and customary international law. 3. Hence option B is correct. _Source: UN Charter 1945 / Vienna Convention on Law of Treaties 1969 / Geneva Conventions 1949 / ICJ Statute / UDHR ICCPR ICESCR — Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States), 1986 ICJ Rep 14_