Which of the following contains rock salt structure?

In an $fcc$ structure,the location of the octahedral void is at ........

The fraction of void space on the body diagonal in an ideal rock salt structure is [Use : $\sqrt{6} = 2.45$]

Diamond has a three-dimensional structure of $C$ atoms formed by covalent bonds. The structure of diamond has a face-centered cubic $(FCC)$ lattice where $50\,\%$ of the tetrahedral voids are also occupied by carbon atoms. The number of carbon atoms present per unit cell of diamond is $......$

Which of the following is a $1:2$ type compound?

In zinc blende structure,the coordination number of $Zn^{2+}$ ion is