Why does dry HCl gas not change the colour of the dry litmus paper?

Q. Why does dry HCl gas not change the colour of the dry litmus paper?

1. Blue litmus becomes dry in presence of dry HCl gas
2. No H O ions will be present, litmus changes colour only in the presence of H O ions
3. HCl gas acts asa dehydrating agent
4. None of the above

Answer: B