The CORRECT statement(s) for cubic close packed (ccp)  three dimensional structure is (are) 

CCP is ABC ABC… type packing 
(a) In the topmost layer, each atom is in contact with 6 at atoms in same layer and 3 atoms below this layer. Thus, the number, of nearest neighbours is 9.
(b)  packing fraction  $=\frac{4\times \frac{4}{3}\pi r^3}{{\left(\frac{4r}{\sqrt{2}}\right)}^3}=\left(0.74\right)$
( c) Each fcc unit has effective no . of atoms = 4
Octahedral void =4
Tetrahedal void =8