Explanation:
XeF4 is the molecule that is planar out of the given options. Let's understand why.

Definitions:
- Planar: A molecule is considered planar if all the atoms lie in the same plane.
- Non-planar: A molecule is considered non-planar if the atoms do not lie in the same plane.

Structure of XeF4:
- XeF4 is the chemical formula for xenon tetrafluoride.
- It consists of one xenon (Xe) atom bonded with four fluorine (F) atoms.
- The Lewis structure of XeF4 shows that there are 4 sigma bonds between xenon and fluorine atoms.
- Additionally, there are two lone pairs of electrons on the xenon atom.

Explanation:
- In XeF4, the central xenon atom is surrounded by four fluorine atoms, forming a square planar geometry.
- The four fluorine atoms are arranged in a square around the central xenon atom, with each fluorine atom bonded to the xenon atom through a single sigma bond.
- The two lone pairs of electrons on the xenon atom are located in the plane of the molecule, perpendicular to the square formed by the fluorine atoms.
- Due to the repulsion between the lone pairs of electrons and the bonding pairs of electrons, the lone pairs occupy two opposite corners of the square, causing a distortion in the molecule's shape.
- This distortion results in a planar structure, where all the atoms lie in the same plane.

Conclusion:
XeF4 is planar because all the atoms (xenon and fluorine) lie in the same plane.