Ordinances may be initiated by petition of registered voters of the city filed with the commission. If the petition accompanying the proposed ordinance is signed by the registered voters in the city equal in number to twenty-five percent of the votes cast for all candidates for mayor at the last preceding city election, and if it contains a request that, unless passed by the commission, the ordinance be submitted to a vote of the registered voters of the city, the commission shall either:
(1) Pass the proposed ordinance without alteration within twenty days after the county auditor's certificate of sufficiency has been received by the commission; or
(2) Immediately after the county auditor's certificate of sufficiency for the petition is received, cause to be called a special election to be held on the next election date, as provided in RCW 29A.04.330, provided that the resolution deadline for that election has not passed, for submission of the proposed ordinance without alteration, to a vote of the people unless a general election will occur within ninety days, in which event submission must be made on the general election ballot.