This question places both N and P. When a question gives you a new rule, you should draw it. N is easiest to draw first, because N only can go in one place:

Next, think where P goes. P has to be between O and S. And S can’t go second or fourth. So in this diagram, there’s only space for P to go second:

The O,S and the vertical line are another improvisation. I’ll be using that in this game to indicate that OPS fill an area, in either order.
I could draw them in a box with a reversible handle, but the way I drew above is faster. And that makes all the difference on logic games.
The question is asking who could go in position 1. From this diagram, only P or S could, so D is CORRECT.

Final sentence is incorrect – it should say, “Only O or S could”.
“The question is asking who could go in position 1. From this diagram, only P or S could, so D is CORRECT. ”
…should read only O or S could, so D is CORRECT.”
Cheers,
Paul