Explanation

(c)
$\mu\ experimental = Dipole\ moment\ \times 10^{- 18}$
$\mu\ theoretical = Bond\ length \times 4.8 \times 10^{- 10}\ esu \times cm$
$Percentage\ ionic\ character = \frac{\mu_{experimental}}{\mu_{theoretical}} \times 100$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = \frac{1.0 \times 10^{- 18} \times 100}{1.25 \times 4.8 \times 10^{- 10} \times 10^{- 8}}$
$= 16.66\%$