Question

Stacking of square packed layers/sheets exactly above one another gives

Answer 1

Square packed layers/sheets are placed exactly above one another to get 3-D closed packing. Here, arrangement of spheres is perfectly aligned horizontally as well as vertically.​ The formed lattice has AAA type arrangement where, A is any layer in the packing.​
Lattice thus generated is simple cubic lattice and its unit cell is simple cubic unit cell.

Thus, option (c) is correct.