Discussion

Answer: A

The correct option is Only (i) can correspond to the unfolded cube in Panel I.

Fold the net with the diamond square as the front face. The square above it in the column becomes the top (its shaded quarter sits at the back right), the square below it becomes the bottom (shaded wedge), and the top square of the column becomes the back (small shaded corner triangle). The rectangle-band square attached to the back face becomes the right face, with its shaded half running horizontally along the upper half, and the half-shaded square at the bottom left becomes the left face.

Cube (i) shows the diamond in front. Give the folded cube a quarter turn about the front-to-back axis so that the left face comes to the top: the half-shaded triangle then lies on top with its shaded half towards the front right, and the former top face comes to the right side with its shaded quarter in the lower back corner. That is exactly what (i) shows.

Cube (ii) shows the small corner triangle in front, so its front is the back face of the net. Bringing that face round to the front by a half turn about the left-right axis puts the bottom wedge on top, as drawn, but it turns the right face's band upside down, still horizontal, along its lower half. Cube (ii) shows that band running vertically, which no folding of this net can produce. So only (i) fits, which rules out the 'only (ii)', 'both' and 'neither' options.