The correct option is C Simple cubic
The edge length or side of the cube, a and the radius of each particle, r are related as a=2r.
The volume of the cubic unit cell =a3=(2r)3=8r3
A simple cubic unit cell contains only 1 atom.
The volume of the occupied space =4πr33
∴Packing efficiency =Volume of one atomVolume of cubic unit cell×100=52.4%