probably destiny.
and it's about the whole budget, not only development costs... activision will probably pump 100m+ just in marketing. they want this to be a huge success for a decade or more and have to invest a huge amount in marketing to let people know about this game. if they can increase the sales with a huge marketing budget and if the game will be good, destiny 2 and 3 will also sell great because of that first huge investment for destiny 1 because many people will be fans then which they wouldn't be without playing destiny 1.
and if it has to sell 10m some of those sales would be not for a full price anymore which cliffy also knows so probably a budget of ~200m for everything and activision needs to get 20 bucks per sold game.
same for watch_dogs which could be also possible but i think activision is best known to pump a lot in marketing (didn't they invest like 200m for marketing of only one cod game?)
