Suppose there is a relation R(A, B, C) with a B+-tree index with search keys (A, B).
1. What is the worst-case cost of finding records satisfying 10 < A < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree?
2. What is the worst-case cost of finding records satisfying 10 < A < 50 and 5 < B < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above?
3. Under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from Part (2)?