Utilize the input text as a context reference, choose the right relationship between 'Vikram Pandit' and 'Citigroup' from the options.
Options: owner of, employer, brand, product/material produced

Last week, Citigroup Inc's ( C.N ) Chief Executive Vikram Pandit said that he, Chairman Win Bischoff, and senior adviser Robert Rubin would not receive bonuses for 2008.
employer