ENERGY • Russian state-owned oil giant Rosneft strengthened its hold on the country's lucrative oil industry when it sealed an agreement to buy TNK-BP, the 50-50 joint venture between British Petroleum and a group of Russian oil oligarchs. The deal will allow Rosneft to leapfrog ExxonMobil Corp. to become the world's largest publicly traded producer of oil and gas, in terms of output, 4.6 million barrels of oil vs. 4.2 million.