; (B) be a citizen of the United States; (C) contract in writing, with the consent of a parent or guardian if a minor, with the Administrator, to— (i) accept an appointment, if offered, as a commissioned officer in the commissioned officer corps of the Administration; and (ii) to serve in the commissioned officer corps for not fewer than 4 years; (D) enroll in— (i) a 4-year baccalaureate program of professional flight and piloting instruction; and (ii) other training or education, including basic officer training, which is prescribed by the Administrator as meeting the preliminary requirement for admission to the commissioned officer corps