Take context from the input text and decide on the accurate relationship between 'Citadel LLC' and 'hedge fund' from the options provided.
Options: operator, industry, director/manager, chairperson

On Monday, it froze a trading account linked to Citadel Securities, a unit of the U.S. group that also owns hedge fund Citadel LLC - the first time in the crackdown that a foreign firm confirmed one of its Chinese accounts had been suspended.
industry