CsBr has b.c.c structure with edge length $4.3 A^{\large\circ}$. The shortest inter ionic distance between $Cs^+$ and $Br^-$ is

Question

$(a)\;3.72A^{\large\circ}\qquad(b)\;1.86A^{\large\circ}\qquad(c)\;7.44A^{\large\circ}\qquad(d)\;4.3A^{\large\circ}$