Why is it ironic that Dr. Manette refuses to listen when Charles tries to tell him his real name?

From the glass menagerie: "suspended in the mist over berchtesgaden, caught in the folds of chamberlain's umbrella." who was chamberlain? a.paul chamberlain: tom's father b.neville chamberlain: prime minister of great britain. c.pedro chamberlain: amanda's drunkard husband d.cornelius chamberlain: gentleman caller for laura