If Electronegativity of H and F atom are given to be 2.1 and 4.0 respectively. What is the % ionic character in H-F bond on the basis of Hannay Smith equation?

Question

$\begin{array}{1 1} a)20\% \\ b) 50\% \\ c)43.035\% \\ d) 35.048\%\end{array}$