Question ID:PT73 S4 Q13 Passage:In early 2003, scientists detected methane in the atmosphere of Mars. Methane is a fragile compound that falls apart when hit by the ultraviolet radiation in sunlight. So any methane in the Martian atmosphere must have been released into the atmosphere relatively recently. Stem:The argument relies on the assumption that Correct Answer Choice:BChoice A:Mars had no methane in its atmosphere prior to 2003 Choice B:all methane in the Martian atmosphere is eventually exposed to sunlight Choice C:methane cannot be detected until it has started to fall apart Choice D:the methane that the scientists detected had been exposed to ultraviolet radiation Choice E:methane in Earth's atmosphere does not fall apart as a result of exposure to ultraviolet radiation