Utilize the input text as a context reference, choose the right relationship between Occidental Petroleum and Petroleum from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

Occidental Petroleum Corporation (NYSE: OXY) Oklahoma-based oil and gas firm Occidental Petroleum came in at number two on the list of highest taxes, with an overall rate of 109.3 percent.

Answer: product_or_material_produced