Let $n$ be an odd number greater than 100 . Consider a binary minheap with $n$ elements stored in an array $P$ whose index starts from 1. Which of the following indices of $P$ do/does NOT correspond to any leaf node of the minheap?

The height of a binary tree is the number of edges in the longest path from the root to a leaf in the tree. The maximum possible height of a full binary tree with 23 nodes is $\_\_\_\_$ . (answer in integer)

Consider a binary tree $T$ in which every node has either zero or two children. Let $n>0$ be the number of nodes in $T$. Which ONE of the following is the number of nodes in $T$ that have exactly two children?

Suppose the values $10,-4,15,30,20,5,60,19$ are inserted in that order into an initially empty binary search tree. Let $T$ be the resulting binary search tree. The number of edges in the path from the node containing 19 to the root node of $T$ is ________ (Answer in integer)