Under the doctrine of CHANGED CIRCUMSTANCES (rebus sic stantibus) in customary international law, treaties may be set aside only where the change:

1. The customary doctrine of REBUS SIC STANTIBUS is codified in VCLT Article 62, restricting its application very narrowly. 2. The conditions: (i) the change is FUNDAMENTAL; (ii) UNFORESEEN; (iii) original circumstances constituted an ESSENTIAL BASIS of consent; (iv) the change RADICALLY TRANSFORMS obligations still to be performed. 3. The ICJ in Gabčíkovo–Nagymaros Project, 1997 ICJ Rep 7, applied the doctrine strictly — finding that Hungary had not met the demanding standard. 4. Cannot apply to boundary treaties. 5. Hence option B is correct. _Source: UN Charter 1945 / Vienna Convention on Law of Treaties 1969 / Geneva Conventions 1949 / ICJ Statute / UDHR ICCPR ICESCR — VCLT Article 62; Gabčíkovo–Nagymaros Project (Hungary/Slovakia), 1997 ICJ Rep 7_