The best option by far is an Inter win. The only reason to want a draw is to give ourselves more options in case Roma go on a good run and Inter fail, but 3rd and 4th are the same and since Inter are 5 points ahead of us there is a much better chance of us getting 4th if Inter beat Roma.
Inter winning is the best scenario for Milan. Any points for Roma is not good for us.
Inter also have the head to head advantage on us so if we finish level on points, they'll be above us so we actually have to gain 6 points to get above them.
But a draw would bring Inter back into the fight and they may well collapse in that case, especially with Juventus and Napoli still to play.
In fact even if Roma won, it's very possible that Inter would lose to Juventus in the next game and we could overtake them and even if Roma were still close to us that group of teams would be fighting for 2 spaces instead of 1 and Atalanta and Lazio play each other in week 35.
Anyway, the main thing is that we win!