$2$ Points

Which XXX would replace the missing statement in the algorithm for inserting a new node in an empty AVL tree? AVLTreelnsert$($tree$,$ node$)\{$ if $($tree cdots root $==$ null$)$if $($ tree rarr root $!=$ null$)$ if $($node cdots$+$ left $==$ null$)$ if $($node cdots left $!=$ null$)$