Which of the following set of properties generally decreases along a period?

The first ionization energy for $Li$ is $5.4 \ eV$ and electron affinity of $Cl$ is $3.61 \ eV$. The $\Delta H$ (in $kJ/mol$) for the reaction $Li_{(g)} + Cl_{(g)} \to Li^{+}_{(g)} + Cl^{-}_{(g)}$ is (if resulting ions do not combine with each other) ($1 \ eV = 1.6 \times 10^{-19} \ J$,$N_A = 6.022 \times 10^{23} \ mol^{-1}$)

Given below are two statements:
Statement-$I$: $C < O < N < F$ is the correct order in terms of first ionization enthalpy values.
Statement-$II$: $S > Se > Te > Po > O$ is the correct order in terms of the magnitude of electron gain enthalpy values.
In the light of the above statements,choose the correct answer from the options given below:

Which element from the following exhibits a diagonal relationship with $Mg$?

Identify the incorrect order.

$(a)$ $Be$ and $Mg$ are alkaline earth metals.
$(b)$ $K^{+}$ has larger radii than $Ca^{2+}$.
$(c)$ All $d$-block elements are transition elements.
$(d)$ $H^{-}$ ion is larger than $F^{-}$.
Incorrect statement is/are