The incorrect order of second ionization energies in the following is

We know that as we go down the group, the values of ionization energy(IE) decrease and as we move across the period from left to right , the value of ionization energy increases gradually.

And, from the above option Rb and K belongs to same group and atomic number of K is 19 and Rb is 37 ,then Ionisation energy of K>Rb.

same trends are possible in case of IE₂.