Molecular polarity from geometry and electronegativity Steps:

• Define polarity: A molecule is polar if electronegativity differences create bond dipoles that don't cancel due to asymmetric geometry.
• Analyze ammonia (NH3): Trigonal pyramidal (AX3E), polar N-H bonds, net dipole—polar.
• Analyze hydrogen sulfide (H2S): Bent (AX2E2), polar S-H bonds, net dipole—polar.
• Analyze boron trifluoride (BF3): Trigonal planar (AX3), symmetric, dipoles cancel—nonpolar; option D missing, ambiguous.

Why B is correct:

• H2S follows VSEPR theory with bent shape and ΔEN (S=2.5, H=2.1) >0.4, yielding net dipole moment per dipole moment law.

Why the others are wrong:

• A. NH3 is polar (pyramidal, net dipole), but question may intend single answer.
• C. BF3 symmetric, no net dipole.
• D. Not enough information.

Final answer: Not enough information.