What should be output for $n = 8$??
In the question it is clearly mentioned as "The minimum size of an array that it may require to store a binary tree with n nodes" , In this case you need to take the best case possible that is Balanced Complete Tree
The minimum size is required is 2Hieght of Tree-1
Hieght of Tree is Log2n+1 (If you take root is in hieght 0)
The minimum size is required is 2log2(n+1) -1
@abcd2 See we are not storing nodes in array in linear manner
Consider we are storing root node in ith location then the left child is stored in (2i)th position and right child of that node is stored in (2i+1)th position. This rule for array representation is true for each and every child.
Yes it will take 15 . Heap is special case of binary Tree
Ans should be 'n' which is quite equal to option A