Which of the Following Is Not an Acceptable Location for an Atom

Multiple Choice

Which of the following is not an acceptable location for an atom in a side-centered primitive cell?

A) (1,1,0)
B) (1, 1/2 ,0)
C) $(1 / 2,1 / 2,1 / 2)$
D) all of the above
E) none of the above