It should come as no surprise that the most popular of these portfolios is that of renowned investor Warren Buffett , CEO of Berkshire Hathaway ( BRK.B ) and one of the richest people in the world.
Utilize the input text as a context reference, choose the right relationship between 'Warren Buffett' and 'Berkshire Hathaway' from the options.
Options: employer, product/material produced, brand, owner of