Planar Molecular Geometries Steps:

• Apply VSEPR theory to predict electron and molecular geometries for each molecule.
• Classify geometries as planar (linear, trigonal planar, bent with coplanar atoms) or non-planar (pyramidal, tetrahedral).
• Check each option to see if all listed molecules have planar geometries.
• Select the option where every molecule meets the planar criterion.

Why D is correct:

• BF3 (trigonal planar, sp² hybridization), CO2 (linear, sp hybridization), and H2O (bent, sp³ with coplanar atoms) all have geometries where all atoms lie in one plane, per VSEPR.

Why the others are wrong:

• A: PH3 is trigonal pyramidal (lone pair distorts to 3D).
• B: NH3 is trigonal pyramidal (lone pair causes non-planar shape).
• C: CH4 is tetrahedral (sp³, 3D arrangement).

Final answer: D