If A is a skew-symmetric matrix of order n , then

The correct answer is Option (2) → $a_{ij}=0, $ where i= j

as $a_{ij}=-a_{ji}$ for skew symmetric matrices.

for $i=j$ (diagonal elements)

$a_{ij}+a_{ji}=0$

$a_{ij}+a_{ij}=0⇒a_{ij}=0$ (where $i = j$)