The cheapest.
My reason: All chains (from the same brand) are made from the same material and to the same dimensional specs.
More expensive chains have cosmetic features that don't affect performance or longevity. These are electroplated components for a shinier look. The cheapest chain are not plated and only have a phosphate coating (brown) that offers mild corrosion resistance. However, a bit of rust on the side plates is neither here nor there and oiling the chain also protects it. As the chain gets more expensive, more parts are plated. First they only plate the outer side plates. Then the outer and inner, on more expensive chains. Then, to make them more expensive, they make them lighter by punching out holes in the side plates and eventually, hollowing out the bushings. None of these features have an effect on life or performance.
Even across brands, chains are dimensionally equivalent, it being controlled by an SI standard. I'm sure really crappy chains do exist but by and large all the reputable brands make quality chains where the price difference is due to cosmetic features.
I buy cheap chains and spend my vanity money elsewhere, I can't think where right now but I'm sure I buy stuff with unnecessary features - maybe it is wine in glass bottles rather than cardboard boxes.