; and (2) by adding at the end the following new subparagraphs: (B) In carrying out the requirement in subparagraph (A) pertaining to the selection of an officer of the reserve component, the Secretary of Defense shall alternate between selecting an officer of the National Guard and an officer of the Reserves no less frequently than every two terms. (C) The Secretary of Defense may waive the requirement under subparagraph (B) regarding the alternating selection of reserve component officers if the Secretary of Defense determines that such action is in the national interest. . 525. Grade of Vice Chief of the National Guard Bureau Section 10505 of title 10, United States Code, is amended by adding at the end the following new subsection: (c) Grade and Exclusion From General and Flag Officer Authorized Strength (1) The Vice Chief of the National Guard Bureau shall be appointed to serve in the grade of general. (2) The Secretary of Defense shall designate, pursuant to subsection (b) of section 526a of this title, the position of Vice Chief of the National Guard Bureau as one of the general officer and flag officer positions to be excluded from the limitations in subsection (a) of such section. . C General service authorities and military records 531. Modification of limitation on enlistment and induction of persons whose score on the Armed Forces Qualification Test is below a prescribed level Section 520(a) of title 10, United States Code, is amended— (1) by striking The number of persons and inserting (1) The number of persons ; (2) by striking may not exceed 20 percent and inserting may not exceed 4 percent