left child of the node labelled 30

right child of the node labelled 5

right child of the node labelled 30

left child of the node labelled 10

10

9

12

13

15

25

63

30

post-order

pre-order

inorder

none of these

any node n_d at level less than d-1 has two sons

it contains log(d)+1 nodes

for any node n_d in the tree with a right descendent at level d lt must have a left son

all of these