Which phrase or sentence in this excerpt from Kurt Vonnegut's "Report on the Barnhouse Effect" demonstrates the use of irony?

Answer:
The correct answer for the question that is being presented above is this one: "B. At ten minutes before H-hour the general came in, shepherding the professor before him. The professor was comfortably attired in sneakers, gray flannels, a blue sweater, and a white shirt open at the neck."
Explanation: