A body centered cubic solid is made up of two elements A and B. Atoms of ‘A’ occupy two corners of the cube. Remaining positions of the unit cell are occupied by the atoms of ‘B’. The formula of the compound is :

Since A occupies 2 corners
Amount of atom A in the cell is $\left(\frac{1}{8}\right)\times 2=\frac{1}{2}$
Then B occupies the body center as well as the rest 6 corner.
So, Amount of atom B in the cell is $\left(\frac{1}{8}\right)\times 6+1=\frac{7}{4}$
$$\begin{gathered} \frac{A}{B}=\frac{{\displaystyle \frac{1}{4}}}{{\displaystyle \frac{7}{4}}} = \frac{1}{7} \\ So it is A{B}_7 \end{gathered}$$

Therefore, the correct option is C AB₇