The net at the top is folded into a cube with the letters outside. Which of the cubes (a) to (d) can NOT be made from it?

Folding gives the opposite pairs P–T, Q–S and R–U, and none of the four cubes shows an opposite pair together. But at the corner where S, T and U meet, the folded net reads S → T → U (top, left, right), while (c) reads S → U → T: a mirror image, so (c) cannot be made.