Reuters: BP Plc said on Saturday the complex “top kill” maneuver to plug its Gulf of Mexico oil well has failed, crushing hopes for a quick end to the largest oil spill in U.S. history already in its 40th day. The beleaguered London-based energy giant said its next option is a “lower marine riser package” that will not plug the well ruptured in a rig blast, but rather capture most of the oil on the sea floor and channel it to the surface for collection. BP Chief Executive Tony Hayward …