In group annuity contracts there shall be a provision specifying the document or documents which shall constitute the entire contract between the parties. The document or documents so specified shall be only:
1. The contract.
2. The contract together with the application of the holder of which a copy is attached thereto.
3. The contract together with the application of the holder of which a copy is attached thereto and the individual applications of annuitants on file with the insurer and referred to therein.