Which of the following expression is correct for packing fraction of NaCl if the ions along with face are diagonally removed?

Options

A. `((13)/(3)pir_(-)^(3)+(16)/(3)pir_(+)^(3))/(8(r_(+)+r_(-))^(3))`
B. `((13)/(3)pir_(-)^(3)+(4)/(3)pir_(+)^(3))/(8(r_(+)+r_(-))^(3))`
C. `((16)/(3)pir_(-)^(3)+(13)/(3)pir_(+)^(3))/(8(r_(+)+r_(-))^(3))`
D. `((4)/(3)pir_(-)^(3)+(13)/(3)pir_(+)^(3))/(8(r_(+)+r_(-))^(3))`

Answer

A