It is really quite rare for a game to make me cry. Or a movie, or a book, or a TV show, or any other form of media. I could probably sit down and count the ones that have, if I tried, and usually it says as much about my state of mind at that particular moment as it does about the game/movie/book/etc. So it's no knock against Dragon Age when I say that the answer is that there isn't one. No scene in any of the games has moved me to literal tears.
That's not to say that there weren't moments that I found affecting or upsetting. A few that come to mind: Leandra's death, particularly the conversations with Gamlen and the LI afterwards; when Hawke let Carver go to the Grey Wardens in the Deep Roads, and also their reunion during the Qunari uprising; Duncan's death; Alistair walking out of the Landsmeet; the sacrifice of the Couslands; learning that Fergus survived; the final defeat of the archdemon.
Also, I suspect that if I ever play a game where Alistair sacrifices himself for my Warden, it might well bring on the tears, even though I would have knowlingly maneuvered my characters into those circumstances.
Complete list of questions
This entry is also posted at http://owlmoose.dreamwidth.org/577277.html. There are currently comments on DW.