The dipole moment of o-dichlorobenzene is $2.60\mathrm{D}$. Assuming only two equal C-Cl bond dipoles in the plane of the ring (directions $60^{\circ }$ apart in ortho, $120^{\circ }$ in meta), the dipole moment of m-dichlorobenzene is closest to

1. A$1.50\mathrm{D}$
2. B$1.30\mathrm{D}$
3. C$2.25\mathrm{D}$
4. D$0\mathrm{D}$