State-owned fuel retailers -- IOC, Bharat Petroleum Corp (BPCL) and Hindustan Petroleum Corp (HPCL) -- revise petrol and diesel prices on 1st and 16th of every month based on average imported cost and rupee-dollar exchange rate in the previous fortnight.
What is the relationship between 'Bharat Petroleum' and 'Petroleum' in the context of the input sentence.
Options: distribution format, publisher, legal form, product/material produced