Wed, Jul 15, 2015, 11:40 BST - UK Markets close in 4 hrs 50 mins When Will It Be Time To Buy Explorers Gulf Keystone Petroleum Limited, Enquest Plc And Tullow Oil plc?
Take context from the input text and decide on the accurate relationship between 'Tullow Oil' and 'Petroleum' from the options provided.
Options: member of, product/material produced, owner of, creator