The question is quite ambiguous.
If the question means
i) it's a min-heap then answer would be O(1), because at worst case we need to check the roots at depth 7, and as we know asymptotic complexity tells the order of growth of time wrt 'n' or input size, here irrespective of n, if it's greater than 7 we only need to check at depth 7 at worst case as I said, even if n is 10, 100, 1000 and so on. So, it's not depending on 'n'.
ii) it's just a binary tree with the least element at the root of the tree then T would be O(nlogn) because at worst case we need to search the entire tree.