The Seven Sisters were independently owned companies that dominated the sale and distribution of oil. There were originally seven companies, but they merged into four
a. Chevron, Exxon, Shell, and BP
b. ExxonMobil, Total, Chevron, and ConocoPhillips
c. BP, Royal Dutch Shell, Chevron, and Mobil
d. Saudi Aramco, Gazprom, ExxonMobil, and PetroChina