Cheap/easy transportation from center Paris to Orly airport?

Question

my flight leaves from Orly at 7:00 am

Answer 1

subway and skytrain

Answer 2

Catch the RER B to the station 'Antony' in the suburb of Arceuil (from the Chatelet-Les Halles station this is about a 35 minute ride). From there you can take Orlyval (automatic métro)  to the airport (about 8 minutes).Orlyval operates between 6:00 a.m. and 11:00 p.m., leaving every 4 to 7 minutes.

Paris city bus line 183 also serves the Orly airport south terminal (Orly Sud). You can catch it at Porte de Choisy métro station (13e arrondissement).

Orlybus, goes to Orly-Sud and Orly-Ouest from the métro/RER station at Denfert-Rochereau (14e arrondissement). Hours of operation are 5:35 a.m. to 11:30 p.m., with departures every 15-20 minutes, and travel time is about 30 minutes.

the fare is 5.80 euros.