A student writes six statements about dipole moments. (i) $\text{SF}_4$ has zero dipole moment, because its four S-F bond dipoles cancel. (ii) $\text{BF}_3$ has zero dipole moment, although each B-F bond is polar. (iii) $\text{CCl}_4$ has zero dipole moment, but $\text{CHCl}_3$ does not. (iv) In the crossed arrow for a bond dipole, the cross is at the negative end. (v) $1\ \text{D}$ equals $3.33564 \times 10^{-30}\ \text{C m}$. (vi) $\text{CO}_2$ has zero dipole moment, but $\text{H}_2\text{O}$ does not. How many of these statements are correct?