Reuters: President Barack Obama’s assistant on energy and climate change said on Tuesday she did not know how a tough White House plan to raise the fuel economy of the U.S. car fleet would affect the ethanol industry. “I don’t know the answer to that,” Carol Browner told reporters in a teleconference about the plan. She said modelers had looked at the issue, but she did not know the answer offhand. Obama obliged the struggling auto industry to make more fuel efficient cars on …