Without access to the specific excerpt from "Dr. Heidegger's Experiment," I can't provide a definitive answer. However, based on general knowledge of Mr. Gascoigne's character in the story, the best description would likely be:
E. Mr. Gascoigne had delusions about his understanding of national politics and people’s rights.
This aligns with his characterization as a man who reminisces about his past political influence and seems detached from reality regarding his former status and relevance. If you can provide the excerpt, I can give a more tailored response.