Analyze the relationship between 'Petrobras' and 'gas' within the context of the input sentence.
Options: product/material produced, chief executive officer, founded by, owned by

SAO PAULO (Reuters) - Brazil's state-run oil firm Petrobras (PETR4.SA) said on Wednesday it had signed a contract to sell its 20 percent stake in the Bijupira and Salema oil and gas fields for $25 million (16 million pounds).
product/material produced