The volume of atoms present in a face-centered cubic unit cell of a metal (r is atomic radius) is :

The correct option is C $\frac{16}{3}\pi r^3$
In a face-centred cubic unit cell, there are 4 atoms.
So the volume of atoms is $=\frac{4\times 4\pi r^3}{3}$

$=\frac{16}{3}\pi r^3$

Hence, the correct option is $\text{D}$