In the context of the input sentence, determine the relationship between 'Kofi Annan' and 'United Nations'.
Options: operator, employer, legal form, manufacturer

"The United Nations engaged – there were initiatives such as the Global Compact, which Kofi Annan first telegraphed in 1999 – which have their heritage in Shell's experience in Nigeria and were a response to what was then a significant anti-globalisation movement
employer