Cal. Rev. & Tax. Code § 20586

For the purposes of Chapter 2 (commencing with Section 20581), Chapter 3 (commencing with Section 20625), Chapter 3.3 (commencing with Section 20639), and Chapter 3.5 (commencing with Section 20640), only one claimant per household each year shall be entitled to postponement. When two or more individuals in a household are qualified as claimants, they may determine who the claimant shall be. Such decision is irrevocable. If the individuals are unable to agree, the matter shall be determined by the Controller and his or her decision shall be final.