WASHINGTON — The senior Pentagon officer overseeing combat operations in Iran told the Senate on Thursday that the destruction of an Iranian school, which Iranian officials said killed 175 people, may have been caused by a U.S. bomb and was the only civilian casualty incident that he was aware of in a campaign of more than 13,600 strikes. Adm. Brad Cooper’s testimony suggested that he believed that the U.S. military’s record since that Feb. 28 strike had been near perfect, a fact belied by investigations from human rights groups and news media organizations. Senators greeted Cooper’s claims with deep skepticism, and a human rights group that investigates civilian casualties in war called it “ridiculous.” Related The U.S. military still has not taken responsibility for the school strike, which Cooper, the head of U.S. Central Command, said remained under investigation. The New York Times has verified damage to 22 schools and 17 healthcare facilities.…