With US$493.78 billion in assets as of June 30, Banco do Brasil SA, is the region's largest bank by almost US$100 billion, followed by Itaú Unibanco Holding SA with US$396.12 billion in assets.
In the context of the input sentence, determine the relationship between 'Unibanco' and 'bank'.
Options: parent organization, creator, original broadcaster, product/material produced