Where should the floor transition from tile to carpet go?

Question

I have 2 rooms planned, one will be tiled and the other will be carpeted with a door opening between them. Where should the tile stop and the carpet begin? In the figure below I have 3 different locations, I think the middle of the door opening, but not sure. The door opening is standard 2x4 wall between the rooms.

Figure 1 - Sample visual with possible locations.

Answer 1

If there's a door, under the door, directly.

Otherwise, either dead center or even with one edge or the other. If there's no door, I'd say bring the carpet up to the edge of the tile, rather than cutting the tile to meet in the middle.

That said - it's a purely aesthetic choice.