Which crystal system does diamond possess?

The crystal system of a compound with unit cell dimensions $a = 0.387 \ nm$,$b = 0.387 \ nm$ and $c = 0.504 \ nm$ and $\alpha = \beta = 90^{\circ}$ and $\gamma = 120^{\circ}$ is:

If the distance between $Na^{+}$ and $Cl^{-}$ ions in sodium chloride crystal is '$Y$' $pm$, the length of the edge of the unit cell will be:

In a monoclinic unit cell,the relation of sides and angles are respectively

The total number of body-centred lattices possible among the $14$ Bravais lattices is:

Which of the following statements is correct?