Only one choice? Hehe, it depends on the climate.
On a hot tropical island it would be SG Skiff Mixture. On a more well tempered it would be Black Mallory. And if really cold and windy, a Marlin Flake. Wouldn’t ask for more in a long time but eventually miss all the others
I would have to bring some rope tobacco, probably SG Brown #4. Easy to store, can be prepared pretty much any way you want (coarse, shag, coin, rubbed out), and is tasty as well. If not a rope then I would have to have some sort of plug.