(a) The Secretary of the Commonwealth and the Attorney General shall serve during the pleasure of the Governor.

(b) The term of the Superintendent of Public Instruction shall be four years.

(c) Except as in this act otherwise provided, the heads of other administrative departments, the Commissioner of the Pennsylvania State Police, the members of independent administrative boards and commissions, of departmental administrative boards and commissions, and of advisory boards and commissions, and departmental administrative officers, shall hold office for terms of four years, from the third Tuesday of January next following the election of a Governor, and until their successors shall have been appointed and qualified: Provided, That the term of the Commissioner of the Pennsylvania State Police appointed prior to the third Tuesday of January, one thousand nine hundred and thirty-nine, shall expire upon that date, or as soon thereafter as his successor shall have been appointed and qualified.