c$)(3$ marks$)$ The method to insert an item into a binary search tree is given below. Complete the code where indicated $(...)$ to permit duplicate insertions of an item.private Node Add$($I item, Node node$)$if $($node $==$ null$)$return new Node $($item$)$ ;elseif $($item$.$ CompareTo $($node$.$Item$)0)\{$node$.$ Left $=$ Add $($item$,$ node.Left$)$ ;return node;$\}$elseif $($item$.$ CompareTo $($node$.$Item$)>0)\{$node$.$Right $=$ Add $($item$,$ node.Right$)$ ;return node;$\}$else$\}.$ In c#