Answer:
B. Irony
Step-by-step explanation:
Option B is the correct answer.
Irony is a literary device that actually refers to the opposite of what somebody meant.
The narrator is actually being ironical. He stated that it is easy to get sentimental about the dead and in order to guard against that, he is still telling a story of Curt Lemon, the dead. Telling the story of Curt Lemon, who has died will eventually invoke sentimental feelings.
So, we can deduce that the narrator is being ironical.