(20) Which of the following statements best describes the primary purpose of the Subpart F income provisions? a. They allow for a deferral of non-U.S.-source income from U.S. taxation. b. They provide certainty as to the U.S. income tax treatment of cross-border transactions. c. They prevent shifting of income from the U.S. to high-tax non-U.S. jurisdictions. d. They prevent shifting of income from the U.S. to low-tax non-U.S. jurisdictions.