Binary Search Tree is a Binary Tree in which the left sub-tree of a node has a value less than or equal to its parent node's value and the right sub-tree of a node has a value greater than or equal to its parent node's value.
Level-order traversal goes level by level in a binary tree.
Post-order traversal first visits the Left Subtree, then the Right Subtree and lastly, the Root.
In-order traversal first visits the Left Subtree, then the Root and lastly, the Right Subtree.
Pre-order traversal first visits the Root, then the Left Subtree and lastly, the Right Subtree.