Answer: intrigued
Step-by-step explanation:
The word that best describes the tone of the passage is intrigued. To be intrigued about something is to be fascinated about a particular thing and want to know more about such thing.
Since the passage explains that Graddy can’t help but wonder about the dinner-table conversations that might have occurred, this shows that Graddy was curious and intrigued.
Therefore, the correct option is C.