We are 4 seniors going to Sitges for an afternoon in September. Our apartment is closer to Passaig de Gracia than Sants Station. Is it Line C2 in direction of Calders, and would it be better to buy a T10 card to include Zone 3 or buy 4 individual tickets, one for each person? Are the T10 cards available to purchase at the PDG station by machine, or do we have to buy at metro station? DH and I made this same trip a couple of years ago but from Sants Station and we bought 2 regular return tickets. Now that we are 4 persons, I just thought the T10 Zone 3 might be a better option. Advice please.