California Code, Penal Code - PEN § 31645

(a) An applicant for a firearm safety certificate shall successfully pass the objective test referred to in Section 31640, with a passing grade of at least 75 percent.  Any person receiving a passing grade on the objective test shall immediately be issued a firearm safety certificate by the instructor, provided that, commencing January 1, 2019, the applicant has acknowledged receipt of the firearm safety warning required by subdivision (d) of Section 31640.

(b) An applicant who fails to pass the objective test upon the first attempt shall be offered additional instructional materials by the instructor, such as a videotape or booklet.  The person may not retake the objective test under any circumstances until 24 hours have elapsed after the failure to pass the objective test upon the first attempt.  The person failing the test on the first attempt shall take another version of the test upon the second attempt.  All tests shall be taken from the same instructor except upon permission by the department, which shall be granted only for good cause shown.  The instructor shall make himself or herself available to the applicant during regular business hours in order to retake the test.