Which of these violin rosins should i get?

All of these are perfectly fine rosins to use. Either the Pirastro Goldflex or the Gold has little flecks of gold inside, which doesn't really make a difference in the rosin, but it looks cool I guess. I might go with one of those, since most violinists use lighter rosin since it's less sticky than dark rosin and allows for a clearer sound when you play.