The dichlorobenzenes have these dipole moments: ortho about $2.5\mathrm{D}$, meta about $1.7\mathrm{D}$ and para $0\mathrm{D}$. Which statements are correct?

1. AThe para isomer has the lowest melting point because it is non-polar.
2. BThe ortho isomer has the largest dipole moment of the three.
3. CThe meta isomer has a larger dipole moment than the ortho isomer.
4. DThe C-Cl bond dipoles of the para isomer cancel.