Which xxx completes the BST search algorithm?
def bstsearch(tree, key):
cur = root
while cur:
if key == cur.data:
return cur
elif xxx:
cur = cur.left
else:
cur = cur.right
return None
a) key > cur.data
b) key < cur.data
c) key == cur.right.data
d) key == cur.left.data
