District means any of the following geographical areas of the State of California:
(a)District 1 shall include the counties of Glenn, Tehama, and Shasta.
(b)District 2 shall include the counties of Mono, Mariposa, Merced, San Benito, Monterey, Madera, Fresno, Tulare, and all counties to the south thereof.
(c)District 3 shall include all counties not included in Districts 1 and 2.