Which statement best supports the RNA world hypothesis?

DNA molecules are a precursor to self-replicating RNA molecules, which are used to build proteins.
Early RNA molecules were able to self-replicate, which helps to explain why all organisms share the same genetic code.
Simpler self-replicating organic molecules preceded RNA and contain genetic information.
The absence of oxygen in Earth's early atmosphere allowed for proteins to catalyze the production of new RNA molecules.