(a) The principal subunit of a department is a division. Each division shall be headed by a director.
(b) The principal subunit of a division is a section. Each section shall be headed by a chief.
(c) If further subdivision is necessary, sections may be divided into subunits which shall be known as branches and which shall be headed by heads, and branches may be divided into subunits which shall be known as units and which shall be headed by supervisors.