Cal. Gov. Code § 31761

Optional settlement 1 consists of the right to elect in writing to have a retirement allowance paid to the member until the member’s death and, if the member dies before receiving in annuity payments the amount of the member’s accumulated contributions at retirement, to have the balance at death paid to the member’s estate or to the natural person, having an insurable interest in the member’s life, as the member nominates by written designation duly executed and filed with the board.