Question ID:PT72 S3 Q4 Passage:It has been hypothesized that our solar system was formed from a cloud of gas and dust produced by a supernova‚ an especially powerful explosion of a star. Supernovas produce the isotope iron-60, so if this hypothesis were correct, then iron-60 would have been present in the early history of the solar system. But researchers have found no iron-60 in meteorites that formed early in the solar system's history, thereby disproving the hypothesis. Stem:Which one of the following is an assumption required by the argument? Correct Answer Choice:EChoice A:If a meteorite is formed early in the solar system's history, it contains chemical elements that are unlikely to be found in gas and dust produced by a supernova. Choice B:Other solar systems are not formed from clouds of gas and dust produced by supernovas. Choice C:Supernovas do not produce significant quantities of any form of iron other than iron-60. Choice D:Researchers have found iron-60 in meteorites that were formed relatively late in the solar system's history. Choice E:If there had been iron-60 present in the early history of the solar system, it would be found in meteorites formed early in the solar system's history.