A Texas Oil Company Extracts Petroleum and Sells It to a Refinery

A Texas oil company extracts petroleum and sells it to a refinery for $1,000.After processing,the refinery sells the gasoline to a wholesaler for $1,500,who then sells it to a gas station for $1,700.The gas station sells it to customers for $2,500.In these transactions,how much has been added to GDP?

A) $1,000
B) $1,500
C) $1,700
D) $2,500
E) $6,700