If the initiative petition is signed by voters not less in number than 20 percent of the entire vote cast within the county for all candidates for Governor at the last gubernatorial election preceding the publication of the notice of intention to circulate an initiative petition, and contains a request that the ordinance be submitted immediately to a vote of the people at a special election, the board of supervisors shall do one of the following:
(a)
Adopt the ordinance without alteration either at the regular meeting at which the certification of the petition is presented, or within 10 days after it is presented.
(b)
Immediately call a special election pursuant to subdivision (a) of Section 1405, at which the ordinance, without alteration, shall be submitted to a vote of the voters of the county.
(c)
Order a report pursuant to Section 9111 at the regular meeting at which the certification of the petition is presented. When the report is presented to the board of supervisors, it shall either adopt the ordinance within 10 days or order an election pursuant to subdivision (b).