Case 4. Sophie is a professor in business at the University of California. She went on sabbatical for an academic year to take courses in Paris University to expand her knowledge of international business and to conduct research. On weekends and during the three-week winter break, Sophie went sight-seeing by herself, but one time gave a lecture in Germany. Sophie has documented her expenses and saved her receipts. Advise Sophie as to the deductibility of her foreign travel expenses.