The correct sequence of elements in decreasing order of first ionisation energy is

Given below are two statements:
Statement $I$: The first ionization energy of $Pb$ is greater than that of $Sn$.
Statement $II$: The first ionization energy of $Ge$ is greater than that of $Si$.
In the light of the above statements,choose the correct answer from the options given below:

The correct values of ionization enthalpies (in $kJ \ mol^{-1}$) of $Si, P, Cl$ and $S$ respectively are

The successive ionisation energy values for an element $X$ are given below. Element $X$ belongs to which group?
$1^{st} \text{ IE} = 410 \ kJ \ mol^{-1}$
$2^{nd} \text{ IE} = 820 \ kJ \ mol^{-1}$
$3^{rd} \text{ IE} = 1100 \ kJ \ mol^{-1}$
$4^{th} \text{ IE} = 1500 \ kJ \ mol^{-1}$
$5^{th} \text{ IE} = 3200 \ kJ \ mol^{-1}$

Among the following elements,the one having the highest ionisation energy is :-

Assertion $(A)$: First ionisation enthalpy of oxygen is less than that of nitrogen.
Reason $(R)$: Atoms with half-filled or completely filled orbitals are less stable.
The correct option among the following is: