Answer :
In "The Importance of Being Earnest", what leads Algernon to suspect that Ernest/Jack is a Bunburyist is when he D. sees an inscription on a cigarette case.
Ernest takes out the cigarette case with the inscription "Uncle Jack" which makes Algernon believe that he is leading a double life.
Ernest takes out the cigarette case with the inscription "Uncle Jack" which makes Algernon believe that he is leading a double life.