Consider the Operation of Deleting the Root of a Binary

Consider the operation of deleting the root of a binary search tree.If the root has two children,then

A) the root node should be removed,then the least node in the right subtree should be deleted and used to replace the root
B) the rood node should be removed,and the deepest rightmost leaf should be used to replace the root
C) the rood node should be removed,the deepest rightmost leaf should be used to replace the root,and then a sift down should be performed to take the root replacement to its proper place
D) the operation should be recursively performed on the two subtrees of the root.