It is known that the fifth layer of a complete binary tree (the root is the first layer) has 8 leaf nodes, then the number of nodes of the complete binary tree is at most ____. A. 47 B. 31 C. 52 D. 39 Which is the answer? why? give full explanation please I have asked this question before but I did not get the right answer, D.39 is wrong, please help me find out the correct answer

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It is known that the sixth layer of a complete binary tree (let the root be the first layer) has eight leaf nodes, then the maximum number of nodes of the complete binary tree is () For this question, the answer is 111