Question $7$

SUBMITTED

Say that we have a binary search tree with the keys $1,2,3,4,5,6,7.$ A preorder traversal of the tree prints the keys in the sequence $4,1,3,2,6,5,7.$ What sequen ce would be printed by a postorder traversal of the tree?

$1.3,1,2,6,5,7,4$

$2.1,2,3,4,5,6,7$

$3.1,2,3,5,6,7,4$

$4.2,3,1,5,7,6,4$