Final answer:
Christine asks Rhoda if she went to the wharf during the picnic, indicating a search for truth about an implied incident.
Step-by-step explanation:
Christine asks Rhoda if she went to the wharf during the picnic. The passage presents Christine questioning Rhoda's whereabouts during a specific event, seeking to confirm her suspicions about something that is not explicitly stated in the text. The focus of the interaction is on establishing an alibi or an involvement in an incident that is implied to be significant within the narrative context.