A compound crystallizes in a body-centered cubic (BCC lattice with a unit cell edge length of 400 pm. The atomic mass of the element is 56 u, and its density is 7.87 \(g/cm^3\). Calculate the percentage of void space in the unit cell.
1
\( 28\% \)
2
\( 32\% \)
3
\( 68\% \)
4
\(74\% \)