law: General Clauses Act, 1897
  15. Power to appoint to include power to appoint ex
  
  officio
  Where, by any 12[Central Act] or Regulation, a power to appoint
  
  any person to fill any office or execute any function is conferred, then,
  
  unless it is otherwise expressly provided, any such appointment, if it is made
  
  after the commencement of this Act, may be made either by name or by virtue of
  
  office.