Fluorine is more electronegative than either boron or phosphorus. What conclusion can be drawn from the fact that $BF_3$ has no dipole moment but $PF_3$ does?

• A
  $BF_3$ is not spherically symmetrical,$PF_3$ is not.
• B
  $BF_3$ molecule must be linear.
• C
  The atomic radius of $P$ is larger than the atomic radius of $B.$
• D
  The $BF_3$ molecule must be planar triangular.