Geraldine is a self-employed consultant in St. Louis, Missouri. She traveled to San Francisco, California, in June and spent two weeks meeting with clients located in the area. She stayed an extra two days on vacation exploring the Bay Area. Which of the following is NOT a deductible business expense on Geraldine's return?

a. Airfare to and from San Francisco.
b. The cost of taking a taxi from her hotel to a client's place of business.
c. The meals and lodging for the extra two days.
d. Any of her meals or lodging, since she tacked on personal vacation days at the end of her trip.