March 10 (Reuters) - The following are the top stories in the Wall Street Journal. Reuters has not verified these stories and does not vouch for their accuracy.

* As a search for clues to the fate of Malaysia Airlines Flight 370 resumed in the waters off Vietnam on Monday, air-safety and antiterror authorities on two continents appeared equally stumped about what direction the probe should take.()

* Western officials are scrambling to loosen Russia's energy stranglehold on Ukraine, the latest sign of growing pressure on Moscow to end the crisis.

The options being considered by officials from Brussels to Washington include larger exports of U.S.-made natural gas, reversing the flow of natural gas through pipelines from Western Europe back into Ukraine, and accelerating plans across Europe to buy more energy from countries other than Russia.()

* A group of newspaper publishers has put the cars.com online marketplace up for sale for as much as $3 billion, hoping to cash in on booming values for e-commerce sites, people familiar with the plans said. ()

* Washington's effort to push banks out of the mortgage-servicing business is propelling the handling of customers' loans into companies such as hedge funds and nonbank financial firms.()

* United Rentals Inc agreed to acquire four companies supplying pumping equipment to the energy industry and other users for a total of $780 million. ()

* Chinese Internet giant Tencent Holdings Ltd is joining forces with China's second-largest e-commerce player, JD.com Inc, in a new partnership aimed at heating up competition with Alibaba Group Holdings Ltd. ()

* As smartphone apps undercut traditional Web searches, they threaten Google's huge ad business. To keep up with mobile habits, Google needs to convince developers to allow links into their apps. ()

* An Environmental Protection Agency review board was pressured by officials at the agency to soften its challenges to an EPA plan for dealing with a highly contaminated radioactive waste site in a St. Louis suburb, a former board member and other people familiar with the matter said. ()

* Federal energy regulators plan to impose new security rules on electric utilities to make sure they protect major substations and other facilities critical to the operation of the electric grid. ()