GRE Logical Reading: ETS-GRE逻辑单题ETS - LHP28M0093X6B080J$

If the statements above are true, which of the following must, on the basis of them, also be true? A. The earliest stars contained only hydrogen. B. Some stars were formed before the universe was two billion years old. C. The carbon in the gas cloud later formed part of some stars. D. No stars identified to date are as old as the gas cloud. E. The gas cloud also contained hydrogen and helium.