Which of the following denotes the number of nodes in a complete binary tree of level 5 ?

The correct answer is (d) 63.

A complete binary tree is a binary tree in which every level, except

The number of nodes in a complete binary tree of level $n$ is given by the formula $2^n-1$.

For a complete binary tree of level 5, the number of nodes is $2^5-1=32-1=63$.

Option (a), 15, is the number of nodes in a complete binary tree of level 3.

Option (b), 25, is the number of nodes in a complete binary tree of level 4.

Option (c), 75, is the number of nodes in a complete binary tree of level 6.