Final answer:
The likely topic of conversation in Ernest Hemingway's "Hills Like White Elephants" is an implied discussion about the possibility of an abortion between a couple.
Step-by-step explanation:
The subject in question is a short story titled "Hills Like White Elephants" by Ernest Hemingway. This story is known for its use of dialogue and subtext to convey a serious and delicate matter between a couple.
Within the text, the couple engages in a veiled conversation with each other, which heavily implies that they are discussing the possibility of the woman having an abortion. The dialogue in the story is subtle and nuanced, full of implications rather than direct statements, which has led to various interpretations by readers and scholars.