The Base-centered orthorhombic cell is like the face-centered orthorhombic cell, but instead of placing an additional lattice point at every face center, we place lattice points on only one of the face types. For instance, if we place an additional lattice point at a=0.5, b=0.5, and c=0, we would call this C-centered as it lies in the ab-plane. Where would the additional lattice point lie in an A-centered orthorhombic cell.