This question refers to the poem Bag of Bones by Dunya Mikhail.
Answer:
The impact of the phrase "What good luck!" at the beginning of the poem she shows us sarcasm in the face of something horrible.
Explanation:
When we speak of the literary tone of a text we refer to the attitude of the narrator to what he or she narrates. In other words, tone is the main emotion that reflects in the narrator's narrative style.
In this case it is sarcasm. No one can feel lucky to have found bones, or to carry a bag of skulls.
That is why the author recounts these horrifying events beginning with a sarcastic line.
