Which of the following statements about stereochemistry in the SN1 reaction of an optically active tertiary alkyl halide are correct?

1. AComplete racemisation is expected only when the product-forming species is a free, symmetrically solvated planar cation.
2. BProduct of retained configuration can arise from nucleophilic capture of the contact ion pair on the side from which the leaving group departed.
3. CSubstrates that give more stable (longer-lived) carbocations show a higher degree of racemisation.
4. DA tertiary substrate in a nucleophilic solvent always gives 100% inversion.