Which excerpt from kurt vonnegut's "report on the barnhouse effect" is an example of irony?

a. professor barnhouse closed his eyes, pursed his lips, and stroked his temples. he held the position for a minute.

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.

c. the tenth still told me nothing. it was only last night that i discovered how it fitted in with the rest. the sentence appeared in my thoughts last night, while i was toying absently with the professor's dice.

d. dutifully and fearfully i watched. a high-pitched humming seemed to come from the inkwell; then it began to vibrate alarmingly.