Elements which occupied position in the Lother Meyer curve, on the peaks, were:

Correct order of IE, in Il period

$\mathrm{Li}<\mathrm{B}<\mathrm{Be}<\mathrm{C}<\mathrm{O}<\mathrm{N}<\mathrm{F}<\mathrm{Ne}$.

The alkali metals sodium, potassium, rubidium, and cesium held positions in the Lother Meyer curve around its maxima. Alkali metals have a large atomic volume and are highly electropositive elements. As a result, choice D is the right response.