Which point groups contain an inversion operator?

The point groups that contain an inversion operator are those that allow for a symmetry operation where every point is inverted through a central point, essentially resulting in an equivalent point located on the opposite side of this center.

The correct choice, which includes Oh, D4h, and D2h, is accurate because:

1. Oh (Octahedral) has multiple symmetry elements, including inversion, due to its highly symmetric structure which corresponds to the symmetry of a cube.

2. D4h (Dihedral), associated with square planar geometries, also contains an inversion center, as every point can be inverted through the center of the molecule.

3. D2h, which relates to linear molecules with two perpendicular planes of symmetry and an inversion center, also exhibits this operator.

In conjunction, these groups illustrate structures that incorporate an inversion center as part of their symmetry operations, making them belong to groups that exhibit this particular symmetry.

The other options do not include point groups that possess an inversion operator, as they either represent lower symmetry or different symmetry elements that do not lead to the inclusion of an inversion point.