Which of the following pairs have the same electronic configuration?

Question

$(1) La^{1+}, Pr, \quad (2) Ce^{4+}, La^{3+} \quad (3) Ce^{3}, Pr^{4+} \quad (4) La^{2+}, Nd$

$\begin {array} {1 1} (1)\;and\;(2) \\ (2) \;and \;(3) \\ (1)\;and \;(3) \\ (2)\;and\;(4) \end {array}$