The correct option is A cu cm
While sq cm is a unit of area, cu m, cu mm and cu mm are units of volume.
Out of m, mm and cm, we have cm to be the most appropriate unit to measure the dimensions of a Rubik's cube. This is because m is a very large unit and mm a small unit when compared to cm.
∴ The most appropriate unit for measuring the volume of a Rubik's cube is cu cm.
(cm × cm × cm = cu cm)