Force of electron \(\Rightarrow \mathrm{F}=\mathrm{eE}\)

\(F=e\left(\frac{2 k \lambda}{r}\right)\)

\(F=\frac{2 k \lambda e}{r}\)

This force will provide required centripetal force

\(\mathrm{F} =\frac{\mathrm{mv}^2}{\mathrm{r}}=\frac{2 \mathrm{k} \lambda \mathrm{e}}{\mathrm{r}}\)

\(\mathrm{v}  =\sqrt{\frac{2 \mathrm{k} \lambda \mathrm{e}}{\mathrm{m}}}\)

\(\mathrm{KE}  =\frac{1}{2} \mathrm{mv}^2=\frac{1}{2} \mathrm{~m}\left(\frac{2 \mathrm{k} \lambda \mathrm{e}}{\mathrm{m}}\right)\)

\(=\mathrm{k} \lambda \mathrm{e}\)

This is constant so option \((2)\) is correct.