Which organization evaluates the status of global nuclear security and maintains the Nuclear Security Index (NSI)?

a) International Atomic Energy Agency (IAEA)
b) Nuclear Threat Initiative (NTI)
c) United Nations Security Council (UNSC)
d) None of above

Nuclear Security Index (NSI) is maintained by Washington-based Nuclear Threat Initiative (NTI), a non-profit entity, which keeps a meticulous record of how countries handle nuclear material.