There's a huge difference in a chicken's development between 2 and 3 months, however, if this bird is 12 weeks old, the oldest you list, its a cockerel. No pullet would have that much comb and wattle and that red this early.
French black copper Marans. See the feathered legs. If only 2 months old certainly a cockerel. If over 3 months and closer to laying could be a pullet. Look in the wingbows for red feathers- only boys will get those. You may have to lift up top feathers to see them but with that much copper in the hackle I would think you would see them easily. If you get a chance post a side shot with it standing on its own in natural light.
I disagree with everyone. It looks like a black sex link pullet to me. We had one that was huge and developed way faster than our others and she now lays beautiful eggs.
I could be wrong. This is just my opinion.