the number of credit hours required to be carried by a full-time student in the course of education or training pursued by the participant during that school year, but in no event may the total period of obligated service of the participant be reduced to less than one year. (2) Service commencement date (A) In general Except as provided in subparagraph (F) of (G), not later than 60 days before the service commencement date of a participant under this section, the Secretary shall notify the participant of that service commencement date. That date is the beginning of the period of obligated service of the participant. (B) Doctors and similar health care professionals In the case of a participant receiving a degree from a school of medicine, osteopathy, dentistry, optometry, or podiatry, the service commencement date of the participant is the date the participant becomes licensed to practice medicine, osteopathy, dentistry, optometry, or podiatry, as the case may be, in a State. (C) Nurses In the case of a participant receiving a degree from a school of nursing, the service commencement date of the participant is the later of— (i) the course completion date of the participant