In the unit cell particles A occupy 8 positions at corner and each is shared by 8 unit cells. So number of particles required for one unit is 1
Particles B occupy 6 positions at the 6 faces and each is shared by 2 unit cells. So number of particles required for one unit is 3
Particles C occupy 12 positions at mid points of 12 edges and each is shared by 4 unit cells. So number of particles required for one unit is 3 .
Again C also occupies unique position at the body center.
By the problem 4 C particles at the edges and one C particle at the body center lying on a plane passing through edge body diagonal are removed.
So the number of C particles in one unit cell becomes = 1/4(12-4) =2
Hence the formula should be AB3C2
Hence our option should be (d), None of these.