12. (D)
Question Type: Unconditional (Orientation)
Remember on Orientation questions, the best strategy is to start with the constraints, NOT the answer choices. This game is kind of an exception, though. Since we have such an amazing diagram, it would be fine to start with the choices and compare them to the three possible frames.
Is it possible to have M O S in Graystone? No! Eliminate (A).
Is it possible to have M O T in Graystone? No! Eliminate (B).
Is it possible to have M S T in Graystone? Yes. And M O S in Landing? No! Eliminate (C).
M S T in Graystone? Yes. And M O T in Landing? Yes, in frame 1 this is possible. (D) is correct.
O S T in Graystone? No! Eliminate (E).