What is the relationship between Petrobras and gas in the context of the input sentence. Choose an answer from: 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.

Thu, Jul 2, 2015, 03:30 BST - UK Markets open in 4 hrs 30 mins Brazil's Petrobras sells $25 million stake in oil, gas field Reuters – 1 hour 57 minutes ago 1,803.50 +17.00

Answer: product_or_material_produced