What is the relationship between 'Berkshire Hathaway' and 'Warren Buffett' in the context of the input sentence.
Options: industry, business division, chairperson, position held

— Warren Buffett is making the biggest bet of his long investment career, a $32.36 billion buyout of Precision Castparts in a deal that will continue to reshape his Berkshire Hathaway conglomerate.
chairperson