Me and a friend were playing Carcassonne earlier and weren't quite sure how to score this field. Does it have 3 or 4 cities in it? Not sure if all 3 meet at the same point and therefore all 3 are in the field or not.
According to the rules:
Each field is worth 3 points per adjacent completed city.
So the city must share a line with the field. It does this for three of the cities. The small vertical city is adjacent to two fields which does not connect to the field with the red meeple, so this one does not count.