Final answer:
The molecule BF3 has a trigonal planar shape, with the fluorine atoms arranged at 120° within the same plane, leading to no net dipole moment. (option B).
Step-by-step explanation:
The shape of a BF₃ molecule is trigonal planar. This is because the molecule consists of three electron groups that orient as far apart as possible, adopting the positions of an equilateral triangle.
The fluorine atoms are positioned at the vertices of this triangle with a F-B-F bond angle of 120°, and all atoms reside in the same plane.
This highly symmetrical shape leads to the molecule having a net dipole moment of zero as the dipoles cancel each other out in three-dimensional space. (option B).