If `a ` stands for the edge length of the cubic system `:` simple cubic, body `-` centred cubic anf face `-` centred cubic, then the ratio of radii of the spheres in these systems will be respectively`:`

Options

A. `(1)/(2) a : (sqrt(3))/(2) a :(sqrt(3))/(sqrt(2))a`
B. `1a: sqrt(3)a : (1) /(2sqrt(2))a`
C. `(1)/(2) a: (sqrt(3))/(4) a: (1)/(2sqrt(2))a`
D. ` (1)/(2) a: sqrt(3)a :(1)/(sqrt(2))a`

Answer

C