Which of the following statements are correct for a binary search tree? a) The root always contains the largest key. b) All keys in the left subtree are always smaller than any key in the...

Which of the following statements are correct for a binary search tree?
a) The root always contains the largest key.
b) All keys in the left subtree are always smaller than any key in the corresponding right subtree.
c) All leaves are located on the same level.
d) Each subtree is also a binary search tree.