Final answer:
The detail from the story that helps determine the theme is when Kim misunderstands the reason the Yang parents do not praise their kids.
Step-by-step explanation:
The detail from the story that helps the reader determine the theme is option A, when Kim misunderstands the reason the Yang parents do not praise their kids. This detail highlights the cultural differences between Kim and the Yang family and shows how misunderstandings can arise due to different customs. The theme of the story is about learning to understand each other despite these cultural differences.