Question ID:PT93 S2 Q7 Passage:The mu mesons generated by cosmic rays just outside Earth's atmosphere travel to Earth at speeds approaching the speed of light. Mu mesons generated in the laboratory, however, are nearly at rest. Mu mesons generated in the laboratory typically decay in much less time than it takes for a mu meson to travel from just outside Earth's atmosphere to our detection apparatus on Earth. If mu mesons traveling through the atmosphere at speeds approaching the speed of light typically decay as fast as they do in the laboratory, then we should detect only about one one-hundredth of the number we actually do detect. Apparently, mu mesons moving at speeds near the speed of light _______. Stem:Which one of the following most logically completes the argument? Correct Answer Choice:DChoice A:take longer to reach Earth than was supposed Choice B:are quite difficult to detect with available equipment Choice C:are much less numerous than previously thought Choice D:decay more slowly than mu mesons almost at rest Choice E:are probably not generated by cosmic rays