Consider the following ionisation enthalpies of two elements 'A' and 'B' 

Element	Ionisation enthalpy $\left(\raisebox{1ex}{$\mathrm{kJ}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{mol}$}\right.\right)$
	1st	2nd	3rd
A	899	1757	14847
B	737	1450	7731

 Which of the following statements is correct?

Both 'A' and 'B' are members of group 2, where 'B' is placed below 'A'.

We notice that the second and third ionisation energies differ significantly. This is typical of metals made of alkaline earth. To create a dipositive ion with a stable electronic structure, they lose 2 valence electrons. It will take a lot of energy to remove the third electron because doing so will disrupt the stable arrangement of the noble gas.

The ionisation energy drops as one descends the group. The needed option is 3 since B's first ionisation energy is lower than A's, hence B comes after A.

Hence, the required option is C)  Both 'A' and 'B' belong to group-2 where 'B' comes below 'A'.