Answer:
A sense of humor, because Faxon has been forgotten by Mrs. Culme.
Step-by-step explanation:
The Triumph of Night by Edith Wharton is a gothic story of George Faxon and his encounter with Lavington and his nephew Frank Rainer. The sense of dread and coldness he experienced while staying with the man forebodes what he will feel in the future after young Frank dies. Faxon then regrets his act of leaving knowing he had the chance to save someone's life but didn't.
Alone, in the deserted remote train station, Faxon was hoping for a coach to get him to his new employer's place when he saw a young man who offered to help him lodge at his uncle's place. On further inquiries, he came to know that Mrs. Culme had seemingly forgotten about him, with Frank declaring that "seven hours is a long time for Mrs. Culme to remember anything". At this remark, Faxon replied "I suppose that's one of the reasons why she needs a secretary", which reveals his sense of humor at the unfortunate event of being forgotten by his own employer.
Thus, the correct is the third option.