Which of the following statements is/are correct?

The co-ordination number of each type of ion in CsCl crystal is 8 

A metal that crystallizes in b.c.c. structure has a co-ordination number of 12

A unit cell of an ionic crystal shares some of its ions with other unit cells

The length of the unit cell in NaCl is 552 pm $\left({\mathrm{r}}_{{\mathrm{Na}}^{+}}=95\mathrm{pm},{\mathrm{r}}_{{\mathrm{Cl}}^{-}}=181\mathrm{pm}\right)$