In Angela’s ashes which sentence in the excerpts does the author most likely use to express humor

This question is missing the options. I've found the complete question online. It is as follows:

In Angela’s Ashes, which sentence in the excerpt does the author most likely use to express humor? Question options:

a) “‘Do you want to know why I’m in the Fever Hospital?’”

b) “‘Especially you, Francis, after thousands of boys prayed for you at the Confraternity.’”

c) “Diphtheria is never allowed to talk to typhoid and visa versa.”

d) “She tells me I better not get the notion she’ll be running up to this part of the world every time I have a little pain or a twinge.”

I believe the best option to be letter c) “Diphtheria is never allowed to talk to typhoid and visa versa.”

Explanation:

Irish author Frank McCourt has filled his memoir "Angela's Ashes" with humor and anecdotes of his childhood. In chapter VIII, Frank is hospitalized.  He is constantly trying to communicate with Patricia, another hospitalized kid who has books with poems that delight Frank. When he is about to find out what happened to the Highwayman and his lover, the nurse comes in and yells, "I told ye there was to be no talking between rooms. Diphtheria is never allowed to talk to typhoid and visa versa." This line is quite humorous for the way it addresses people and diseases. It's as if Frank and Patricia are no longer people, as if they have become the diseases they have. However, diseases don't talk; it is the sick people who do.

the answer is irony!

the words "slavery," "devils," and "murderer" evoke a sense of disgust.