What is the spatial relation betweeen the red block and the green block?
(A) The red block is directly above the green block, and they are in the same stack.
(B) The red block is directly below the green block, and they are in the same stack.
(C) The red block and the green block are at different stacks.
(D) At least one of the red block and the green block does not exist in the presented configurations.