Oil posted the biggest weekly decline since November as traders await proof that OPEC and other producers are following through on promises to cut production. Futures declined 1.2 percent in New York on Friday and slid 3 percent this week. Saudi Arabia reduced output to less than 10 million barrels a day and will consider renewing its pledge to trim supply in six months, according to Energy Minister Khalid al-Falih. Still, until monthly production data is released, “these claims cannot be verified,” according to Commerzbank AG. The U.A.E. doesn’t intend to reduce output more than was agreed upon with OPEC in November and a tanker is said to sail to Libya’s Zawiya port to load Sharara crude. Oil has advanced since the deal among members of the Organization of Petroleum Exporting Countries and 11 other nations to temper global supply. It has been unable to sustain its rally above […]