Consider a node X in a binary tree T$.$ Let Y be the in$-$order successor of X$.$ This means that in the in$-$order traversal of T$,$ nodes X and Y appear one after the other. We know that X has two children $($or child sub$-$trees$).$ Which of the following statements is true about the in$-$order successor Y of node X$?$

$1$ point

Y is the leftmost node in the right subtree of X

Y is parent of X

Y is the rightmost node in the right subtree of X

Y is the leftmost node in the left subtree of X