Question ID:PT22 S4 Q5 Passage:Astronaut:  Any moon, by definition, orbits some planet in a solar system. So, the moons in solar system S4 all orbit the planet Alpha. Stem:The astronaut's conclusion follows logically if which one of the following is assumed? Correct Answer Choice:CChoice A:There is only one moon in S4. Choice B:Every moon in S4 orbits the same planet. Choice C:Alpha is the only planet in S4. Choice D:Every planet in S4 is orbited by more than one moon. Choice E:There is at least one moon that orbits Alpha.