Which of the following contains rock salt structure?

The radius of divalent cation $A^{+2}$ is $94 \, pm$ and divalent anion $B^{-2}$ is $146 \, pm$. The structure of compound $AB$ is

The number of octahedral voids in a $BCC$ structure is:

$A$ crystal is made of particles $X$ and $Y$. $X$ forms $fcc$ packing and $Y$ occupies all the octahedral voids. If all the particles along one body diagonal are removed,then the formula of the crystal would be:

The unit cell of diamond is composed of:

$A$ compound made of elements $A$ and $B$ forms an $fcc$ structure. Atoms of $A$ are at the corners and atoms of $B$ are present at the centres of the faces of the cube. What is the formula of the compound?