For identical spheres of radius $r$ arranged in simple cubic (sc), bcc and fcc lattices, which statements are correct?

1. AThe coordination numbers are 6, 8 and 12 respectively.
2. BIn bcc the edge is $a=2\sqrt{2}r$.
3. CThe packing efficiencies are about 52%, 68% and 74% respectively.
4. DIf atomic mass and radius are the same, the density order is fcc $>$ bcc $>$ sc.