Upon receiving an initiatory or referendary petition from the Clerk, the Council 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;
(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.