Hi theamazingrace! Sometimes you'll get a question like this that asks, "the game is completely determined if which of the following is true?" We call these Justify Logic Game questions. You asked:
So, when a question says "completely determine" does that mean it has to work for all possible placements?
In a word - no. Instead, what these questions are basically asking is: which answer choice, if it were true, would allow us to figure out where every single variable
in the game for sure goes? So our right answer will leave us with just one possible scenario for the entire game.
So like Jeremy explained above, if we know that S goes twice, we can figure out where every single variable in the game goes. We've "completely determined" the game.
On the other hand, if (as answer choice D suggests) we know that R goes twice, we can't
figure out where every single variable in the game goes. In fact, we can't even figure out where R goes! (It could go in 2 and 4 like you said; but it could also go in say, 1 and 3).
These Justify questions can be tricky. Oftentimes they're worth doing near the end of that particular game, so that you have a better sense of which variable placements really allow all the other variables to fall into place.
Hope that helps!