I'd say the two hills on the side of the river are probably the 2 good choices here. Settling on Flood Plains removes the Flood plains, leaving you will a really horrible base tile. Hill is not much better, but it's at least +1 Production, that will help the city to get infrastructure up a bit faster.
I personally would probably prefer the southern hill, because it has the basalt that will come in handy once the city is out of initial growth phase - and of course, it's just closer to the existing city and still gets a ton of resources, while the place in the north really only gets you the silica in the desert and the float stone, but that tile has a low amount of floatstone anyway and float stone as a tile is rather useless.
I think there's also a good case to be made for the northern hill, because it can support a bigger population by adding in the water tiles. But then again, that city won't grow to 22+ for the additional trade route on either of these spots and raw population is not worth that much in BE, so I'd still go for the southern hill for a fast-growing, compact city.
