In a solid ‘AB’ having the NaCl structure, ‘A’ atoms occupy the corners and face centres of the cubic unit cell but all the face-centred atoms along one of the axes are removed and ‘B’ atoms occupy octahedral voids, then the resultant stoichiometry of the solid is

Since A atoms occupy the corners of the cubic unit cell, the number of atoms occupying the corners is 1. If all the face-centered atoms along one of the axes are removed, then only 4 faces remain, which counts in total to 2 atoms of A. B is present in octahedral voids, so the total number of atoms of B is 4. Hence the correct option is option (d)