Solution :
D) is correct.
A full binary tree is a tree in which every node other than the leaves has two children. A complete binary tree is a tree in which every level, except possibly the last, is completely filled, and all nodes are as far left as possible.A) is incorrect. For example, the following Binary tree is neither complete nor full 12
/
20
/
30B) is incorrect. The following binary tree is complete but not full 12
/ \
20 30
/
30C) is incorrect. Following Binary tree is full, but it is not complete 12
/ \
20 30
/ \
20 40D) is correct. As all above options are incorrect.