Upon receiving an initiatory or referendary petition from the Clerk, the Commission shall within thirty (30) days, either;
(a) If it be an initiatory petition, adopt the ordinance as submitted in the petition or determine to submit the proposal to the electors of the city; or
(b) If it be a referendary petition, repeal the ordinance to which the petition refers or determine to submit the proposal to the electors of the city;