The correct answer is A: by creating a sense of urgency and intrigue as Selden observes Miss Bart.
In the passage, tension is created through Selden's surprise and curiosity upon encountering Miss Bart in an unusual setting, which sparks his interest and speculation about her situation. Her aimless demeanor and the fact that she is waiting for someone add to the intrigue, making the reader wonder about her intentions and the implications of their meeting.