For electron gain enthalpies of the elements denoted as Δ eg H , the incorrect option is :

Electron gain enthalpy becomes more negative across a period and becomes less negative as we go down the group. As all the pairs of elements given from comparision, each pair of element belong to the same group. Based on the fact option C is incorrect. Data for electron gain enthalpy is given below:
(A) ${\mathrm{\Delta }}_{\mathrm{eg}}\mathrm{H}\left(\mathrm{Cl}\right)<{\mathrm{\Delta }}_{\mathrm{eg}}\mathrm{H}\left(\mathrm{F}\right)$

$(-345) (-328)$ correct

(B) ${\mathrm{\Delta }}_{\mathrm{eg}}\mathrm{H}\left(\mathrm{Se}\right)<{\mathrm{\Delta }}_{\mathrm{eg}}\mathrm{H}\left(\mathrm{S}\right)$

$(-195) (-200)$ Incorrect

(C) ${\mathrm{\Delta }}_{\mathrm{eg}}\mathrm{H}\left(\mathrm{I}\right)<{\mathrm{\Delta }}_{\mathrm{eg}}\mathrm{H}\left(\mathrm{At}\right)$ 

$(-295) (-270)$ correct

(D) ${\mathrm{\Delta }}_{\mathrm{eg}}\mathrm{H}\left(\mathrm{Te}\right)<{\mathrm{\Delta }}_{\mathrm{eg}}\mathrm{H}\left(\mathrm{Po}\right)$ 

$(-190) (-183)$correct