The possible set of quantum numbers $(n,l,m,s)$ of the last electron of unipositive potassium ion :

Solution:

From the given options their is no possible set of quantum numbers $(n,l,m,s)$ of the last electron of unipositive potassium ion.

The electronic configuration of potassium ion is,

${ }_{19}\mathrm{K}+=1s^{2}2s^{2}2p^{6}3s^{2}3p^6$

  It is observed that the last $e^{-}$ goes into 3p subshell

The value of the quantum number are, $n=3;l=1;m=-1,0,1;s=+\frac{1}{2},-\frac{1}{2}$.

Hence, the option D is correct.