V 3.57 Predict which bond in each of the following groups \begin{aligned} &\text { will be the most polar: }\\ &\text { (a) } \mathrm{C}-\mathrm{F}, \mathrm{Si}-\mathrm{F}, \mathrm{Ge}-\mathrm{F} ;(\mathrm{b}) \mathrm{C}-\mathrm{H}, \mathrm{Si}-\mathrm{H}\\

&\mathrm{Sn}-\mathrm{H} ;(\mathrm{c}) \mathrm{A}\rfloor-\mathrm{Br}, \mathrm{Ga}-\mathrm{Br} ;(\mathrm{d}) \mathrm{As}-\mathrm{Br}, \mathrm{Sb}-\mathrm{Br} \end{aligned}