The insurance authorized by this part may be provided by:

1. (a) Self-insurance, which may be, but is not required to be, funded by appropriations to establish or maintain reserves for self-insurance purposes.
2. (b) Insurance in any insurer authorized to transact such insurance in this state.
3. (c) Insurance secured in accordance with Chapter 6 (commencing with Section 1760) of Part 2 of Division 1 of the Insurance Code.
4. (d) Participation by a hospital district and its medical staff in a reciprocal or interinsurance exchange as provided in Section 1284 of the Insurance Code.
5. (e) Any combination of insurance authorized by subdivisions (a), (b), (c), and (d).