Using the labels from this picture:
A settles on plains which increases their food value without having to irrigate. It leaves access to one hill which means the possibility of iron.
C being surrounded by rivers on 3 sides makes it easier to defend (rivers give a defensive bonus when attacking across them). On the other hand it also gives a movement penalty to units moving out of the city in 6 of 8 possible directions.
D moves away from both hills so limits our access to resources.
E leaves both hills within range of the city.
B is protected by rivers from 3 of 8 directions and keeps one hill.
So far we have people speaking up for B, C, D, and E, with building on the forest to the south also being mentioned. I don't like moving S because we lose the ability to harvest the forest.