What do the terms “buttonholed” and “buttonholing” mean in this part of the selection

The correct answer is D detain someone for conversation.

“Buttonholed” and “buttonholing” refer to the act of stopping someone to engage them in conversation, often unexpectedly. This term comes from the idea of grabbing someone by their buttonhole to hold them in place while you speak to them, suggesting a sense of urgency or importance in the conversation. If you have any more questions or need further clarification, feel free to ask!