Which laptop is the best of these for gaming?

Just out of them three i would say the top link, simply because it has the highest memory and for gaming that is essential. (By gaming i presume you mean PC game disk and not online gaming). However it also depends what game you want to play, games like sims will not run on any of those.
Also on all of them the processor is low, meaning games will run pretty slow.

I understand this probably isn't the answer you wanted, but if i were getting a gaming laptop it wouldnt be either of those as i doubt many games would run on them. However i'm not an epert so take what i say with a pinch of salt.

This doesn't really answer your question, but when looking for a gaming laptop you want one that has a graphics card in it. Most games rely on the graphics card, so even if your processor is only an i3 if you have a good graphics card you should be able to play most games